KR102518821B1 - Method for transmitting uplink control information and apparatus therefor - Google Patents

Abstract

In the method for transmitting uplink control information using a physical uplink shared channel (PUSCH) in a wireless communication system according to an embodiment of the present invention, the method is performed by a terminal, Receiving downlink control information including information on the accumulated number of physical downlink shared channel (PDSCH) transmissions of a cell group for a UE, using the accumulated number of PDSCH transmissions to perform the uplink It may include coding control information and transmitting the coded uplink control information through the physical uplink shared channel.

Description

Method for transmitting uplink control information and apparatus therefor

The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting uplink control information.

Various devices and technologies, such as smart phones and tablet PCs, that require machine-to-machine (M2M) communication and high data transmission rates are appearing and spreading. Accordingly, the amount of data required to be processed in the cellular network is increasing very rapidly. In order to satisfy such rapidly increasing data processing requirements, carrier aggregation technology and cognitive radio technology are used to efficiently use more frequency bands, and data capacity transmitted within a limited frequency is increased. Multi-antenna technology and multi-base station cooperation technology are developing. In addition, the communication environment is evolving in a direction in which the density of nodes that user devices can access in the vicinity increases. A node refers to a fixed point equipped with one or more antennas and capable of transmitting/receiving a wireless signal with a user equipment. A communication system having a high density of nodes may provide a communication service of higher performance to a user device through cooperation between nodes.

This multi-node cooperative communication method in which a plurality of nodes communicate with user equipment using the same time-frequency resources is superior to the conventional communication method in which each node operates as an independent base station and communicates with user equipment without mutual cooperation. It has much better performance in terms of data throughput.

Multi-node systems cooperate using multiple nodes, each node acting as a base station or access point, antenna, antenna group, radio remote header (RRH), or radio remote unit (RRU). carry out communication Unlike a conventional centralized antenna system in which antennas are concentrated in a base station, in a multi-node system, the plurality of nodes are usually spaced apart at regular intervals or more. The plurality of nodes may be managed by one or more base stations or base station controllers that control the operation of each node or schedule data to be transmitted/received through each node. Each node is connected to a base station or base station controller that manages the corresponding node through a cable or a dedicated line.

Such a multi-node system can be regarded as a kind of multiple input multiple output (MIMO) system in that distributed nodes can transmit/receive different streams at the same time to communicate with a single or multiple user devices. However, since the multi-node system transmits signals using nodes distributed in various locations, the transmission area to be covered by each antenna is reduced compared to antennas provided in the existing centralized antenna system. Accordingly, transmission power required for each antenna to transmit a signal can be reduced in a multi-node system, compared to an existing system in which MIMO technology is implemented in a centralized antenna system. In addition, since the transmission distance between the antenna and the user device is shortened, path loss is reduced and high-speed data transmission is possible. Accordingly, the transmission capacity and power efficiency of the cellular system can be increased, and communication performance of relatively uniform quality can be satisfied regardless of the position of the user device in the cell. Also, in a multi-node system, since base station(s) or base station controller(s) connected to a plurality of nodes cooperate in data transmission/reception, signal loss occurring in the transmission process is reduced. In addition, when nodes located at a certain distance or more perform cooperative communication with user equipment, correlation and interference between antennas are reduced. Therefore, according to the multi-node cooperative communication method, a high signal to interference-plus-noise ratio (SINR) can be obtained.

Because of the advantages of such a multi-node system, in order to reduce base station expansion costs and backhaul network maintenance costs in next-generation mobile communication systems, while expanding service coverage and improving channel capacity and SINR, multi-node systems are It is emerging as a new basis for cellular communication in parallel with or replacing the centralized antenna system.

The present invention is a method for transmitting uplink control information, and proposes more efficient channel state reporting and appropriate scheduling accordingly.

The technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

A method for transmitting uplink control information by a terminal configured with a number of downlink cells exceeding 5 in a wireless communication system according to an embodiment of the present invention using a physical uplink shared channel (PUSCH) , wherein the method is performed by the terminal and includes information on the accumulated number of physical downlink shared channel (PDSCH) transmissions of a cell group composed of one or more downlink cells for the terminal. Receiving link control information, coding the uplink control information using the accumulated number of PDSCH transmissions, and transmitting the coded uplink control information through the physical uplink shared channel. there is.

Additionally or alternatively, the cumulative number of PDSCH transmissions may be an accumulated value up to the point at which the downlink control information is received.

Additionally or alternatively, the cumulative number of PDSCH transmissions may be assigned in ascending time-first order.

Additionally or alternatively, the method may be performed per cell group.

Additionally or alternatively, the downlink control information may be received in a UE-specific search space.

Additionally or alternatively, the uplink control information may include a hybrid automatic repeat request (HARQ) ACK.

Additionally or alternatively, the physical uplink shared channel may include uplink resources for each cell group.

As a terminal configured to transmit uplink control information using a physical uplink shared channel (PUSCH) in a wireless communication system according to an embodiment of the present invention and a number of downlink cells exceeding 5 are set, , The terminal includes a radio frequency (RF) unit and a processor configured to control the RF unit, and the processor includes a physical downlink shared channel of a cell group consisting of one or more downlink cells for the terminal. Receive downlink control information including information on the cumulative number of shared channel (PDSCH) transmissions, code the uplink control information using the cumulative number of PDSCH transmissions, and convert the coded uplink control information to It may be configured to transmit through the physical uplink shared channel.

The above problem solving methods are only some of the embodiments of the present invention, and various embodiments in which the technical features of the present invention are reflected are based on the detailed description of the present invention to be detailed below by those skilled in the art. can be derived and understood.

According to an embodiment of the present invention, uplink control information can be efficiently transmitted.

The effects that can be obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

The accompanying drawings, which are included as part of the detailed description to aid understanding of the present invention, provide examples of the present invention and explain the technical idea of the present invention together with the detailed description.
1 illustrates an example of a radio frame structure used in a radio communication system.
2 shows an example of a downlink/uplink (DL/UL) slot structure in a wireless communication system.
3 illustrates a downlink (DL) subframe structure used in a 3GPP LTE/LTE-A system.
4 shows an example of an uplink (UL) subframe structure used in a 3GPP LTE/LTE-A system.
5 shows a link structure between downlink and uplink.
6 shows operations related to DAI.
7 shows an example of UCI resource mapping.
8 illustrates a logical resource area for UCI according to an embodiment of the present invention.
9 illustrates an example of allocation of UCI resources for each CG according to an embodiment of the present invention.
10 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
11 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
12 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
13 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
14 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
15 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
16 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
17 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
18 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
19 illustrates an example of allocation of UCI resources to each CG according to an embodiment of the present invention.
20 illustrates a DCI format according to an embodiment of the present invention.
21 illustrates a DCI format according to an embodiment of the present invention.
22 illustrates an example of UCI resource mapping for each physical uplink shared control channel (PUSCH) resource according to an embodiment of the present invention.
23 shows a block diagram of an apparatus for implementing embodiment(s) of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below in conjunction with the accompanying drawings is intended to describe exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, one skilled in the art recognizes that the present invention may be practiced without these specific details.

In some cases, in order to avoid obscuring the concept of the present invention, well-known structures and devices may be omitted or may be shown in block diagram form centering on core functions of each structure and device. In addition, the same reference numerals are used to describe like components throughout this specification.

In the present invention, user equipment (UE) may be fixed or mobile, and various devices that transmit and receive user data and/or various control information by communicating with a base station (BS) belong to this category. UE is a Terminal Equipment (MS), a Mobile Station (MS), a Mobile Terminal (MT), a User Terminal (UT), a Subscribe Station (SS), a wireless device, a Personal Digital Assistant (PDA), and a wireless modem (wireless modem). modem), handheld device, etc. In addition, in the present invention, a BS generally refers to a fixed station that communicates with a UE and/or other BSs, and exchanges various data and control information with the UE and other BSs. The BS includes an Advanced Base Station (ABS), a Node-B (NB), an evolved-NodeB (eNB), a Base Transceiver System (BTS), an access point, a processing server (PS), and a transmission point (TP). ) may be referred to by other terms. In the following description of the present invention, a BS is collectively referred to as an eNB.

In the present invention, a node refers to a fixed point capable of transmitting/receiving a wireless signal by communicating with a user equipment. Various types of eNBs can be used as nodes regardless of their names. For example, a BS, NB, eNB, pico-cell eNB (PeNB), home eNB (HeNB), relay, repeater, etc. may be a node. Also, a node may not be an eNB. For example, it may be a radio remote head (RRH) or a radio remote unit (RRU). RRH, RRU, etc. generally have a power level lower than that of the eNB. Since RRH or RRU (hereinafter referred to as RRH/RRU) is generally connected to an eNB through a dedicated line such as an optical cable, compared to cooperative communication by eNBs connected through a wireless line, RRH/RRU and eNB Cooperative communication by can be performed smoothly. At least one antenna is installed in one node. The antenna may mean a physical antenna, an antenna port, a virtual antenna, or an antenna group. A node is also called a point. Unlike a conventional centralized antenna system (CAS) (i.e., a single node system) in which antennas are centralized in a base station and controlled by one eNB controller, in a multi-node system A plurality of nodes are usually located apart from each other by a predetermined interval or more. The plurality of nodes may be managed by one or more eNBs or eNB controllers that control the operation of each node or schedule data to be transmitted/received through each node. Each node may be connected to an eNB or an eNB controller managing the corresponding node through a cable or a dedicated line. In a multi-node system, the same cell identity (ID) or different cell IDs may be used for signal transmission/reception to/from a plurality of nodes. When a plurality of nodes have the same cell ID, each of the plurality of nodes operates like a partial antenna group of one cell. If nodes in a multi-node system have different cell IDs, this multi-node system can be regarded as a multi-cell (eg, macro-cell/femto-cell/pico-cell) system. When multiple cells formed by each of a plurality of nodes are configured in an overlay form according to coverage, a network formed by the multiple cells is particularly referred to as a multi-tier network. The cell ID of the RRH/RRU and the cell ID of the eNB may be the same or different. When the RRH/RRU and the eNB use different cell IDs, both the RRH/RRU and the eNB operate as independent base stations.

In the multi-node system of the present invention to be described below, one or more eNBs or eNB controllers connected to a plurality of nodes control the plurality of nodes to simultaneously transmit or receive signals to or from the UE through some or all of the plurality of nodes. can Although there are differences between multi-node systems according to the entity of each node, the type of implementation of each node, etc., these multi-node systems in that a plurality of nodes together participate in providing communication services to the UE on a predetermined time-frequency resource. The systems differ from single node systems (eg, CAS, conventional MIMO systems, conventional relay systems, conventional repeater systems, etc.). Accordingly, embodiments of the present invention relating to a method for performing data cooperative transmission using some or all of a plurality of nodes can be applied to various types of multi-node systems. For example, a node usually refers to an antenna group located apart from other nodes at a predetermined interval or more, but embodiments of the present invention described later may be applied even when a node refers to an arbitrary antenna group regardless of the interval. For example, in the case of an eNB equipped with an X-pole (cross polarized) antenna, the embodiments of the present invention can be applied assuming that the eNB controls a node composed of an H-pole antenna and a node composed of a V-pole antenna. .

A node that transmits/receives a signal through a plurality of transmit (Tx)/receive (Rx) nodes, transmits/receives a signal through at least one node selected from among a plurality of transmit/receive nodes, or transmits a downlink signal. A communication technique capable of differentiating the node receiving the uplink signal from the multi-eNB MIMO or CoMP (Coordinated Multi-Point TX/RX) is called. Among such cooperative communication between nodes, cooperative transmission techniques can be largely divided into joint processing (JP) and scheduling coordination. The former may be divided into joint transmission (JT) / joint reception (JR) and dynamic point selection (DPS), and the latter may be divided into coordinated scheduling (CS) and coordinated beamforming (CB). DPS is also called dynamic cell selection (DCS). Compared to other cooperative communication techniques, when JP among cooperative communication techniques between nodes is performed, more diverse communication environments can be formed. Among JPs, JT refers to a communication technique in which a plurality of nodes transmit the same stream to the UE, and JR refers to a communication technique in which a plurality of nodes receive the same stream from the UE. The UE/eNB restores the stream by synthesizing signals received from the plurality of nodes. In the case of JT/JR, since the same stream is transmitted from/to a plurality of nodes, reliability of signal transmission can be improved by transmission diversity. DPS in JP refers to a communication technique in which a signal is transmitted/received through a node selected according to a specific rule among a plurality of nodes. In the case of DPS, since a node having a good channel condition between the UE and the node is usually selected as a communication node, reliability of signal transmission can be improved.

Meanwhile, in the present invention, a cell refers to a certain geographical area in which one or more nodes provide communication services. Therefore, in the present invention, communicating with a specific cell may mean communicating with an eNB or node that provides a communication service to the specific cell. In addition, the downlink/uplink signal of a specific cell means a downlink/uplink signal from/to an eNB or a node providing a communication service to the specific cell. A cell providing an uplink/downlink communication service to a UE is specifically referred to as a serving cell. In addition, the channel state/quality of a specific cell means the channel state/quality of a channel or communication link formed between an eNB or node providing a communication service to the specific cell and a UE. In a 3GPP LTE-A based system, the UE transmits a downlink channel state from a specific node on a channel CSI-RS (Channel State Information Reference Signal) resource allocated to the specific node by the antenna port (s) of the specific node It can be measured using CSI-RS(s) that In general, adjacent nodes transmit corresponding CSI-RS resources on CSI-RS resources orthogonal to each other. The fact that CSI-RS resources are orthogonal means that CSI-RSs are allocated according to CSI-RS resource configuration, subframe offset, transmission period, etc. that specify symbols carrying CSI-RSs and subcarriers. This means that at least one of the CSI-RS sequence and the subframe configuration specifying the subframes are different from each other.

In the present invention, Physical Downlink Control CHannel (PDCCH) / Physical Control Format Indicator CHannel (PCFICH) / Physical Hybrid Automatic Retransmit Request Indicator CHannel (PHICH) / Physical Downlink Shared CHannel (PDSCH) are Downlink Control Information (DCI) / CFI ( Control Format Indicator) / downlink ACK / NACK (ACKnowlegement / Negative ACK) / means a set of time-frequency resources or a set of resource elements carrying downlink data In addition, PUCCH (Physical Uplink Control CHannel) / PUSCH (Physical Uplink Shared CHannel / PRACH (Physical Random Access CHannel) means a set of time-frequency resources or a set of resource elements carrying UCI (Uplink Control Information) / uplink data / random access signal, respectively. , PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH, or a time-frequency resource or resource element (RE) assigned to or belonging to PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH RE or PDCCH /PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH resource. Hereinafter, the expression that the user equipment transmits PUCCH/PUSCH/PRACH is uplink control information/uplink data on or through PUSCH/PUCCH/PRACH, respectively. / It is used in the same meaning as transmitting a random access signal In addition, the expression that the eNB transmits PDCCH / PCFICH / PHICH / PDSCH transmits downlink data / control information on or through PDCCH / PCFICH / PHICH / PDSCH, respectively. It is used in the same sense as sending.

1 illustrates an example of a radio frame structure used in a radio communication system. In particular, FIG. 1(a) shows a frame structure for frequency division duplex (FDD) used in a 3GPP LTE/LTE-A system, and FIG. 1(b) shows a frame structure used in a 3GPP LTE/LTE-A system. It shows a frame structure for time division duplex (TDD).

Referring to FIG. 1, a radio frame used in a 3GPP LTE/LTE-A system has a length of 10ms (307200Ts) and is composed of 10 equally sized subframes (SF). Numbers may be assigned to each of the 10 subframes in one radio frame. Here, Ts represents the sampling time and is expressed as Ts = 1/(2048*15 kHz). Each subframe has a length of 1 ms and consists of 2 slots. 20 slots in one radio frame may be sequentially numbered from 0 to 19. Each slot has a length of 0.5 ms. The time for transmitting one subframe is defined as a transmission time interval (TTI). Time resources may be classified by radio frame numbers (or radio frame indexes), subframe numbers (or subframe numbers), slot numbers (or slot indexes), and the like.

A radio frame may be configured differently according to a duplex mode. For example, in the FDD mode, since downlink transmission and uplink transmission are distinguished by frequency, a radio frame includes only one of a downlink subframe or an uplink subframe for a specific frequency band. Since downlink transmission and uplink transmission are distinguished by time in the TDD mode, a radio frame includes both a downlink subframe and an uplink subframe for a specific frequency band.

Table 1 illustrates a DL-UL configuration of subframes in a radio frame in TDD mode.

DL-UL configuration Downlink-to-Uplink Switch-point periodicity Subframe number 0 One 2 3 4 5 6 7 8 9 0 5ms D S U U U D S U U U One 5ms D S U U D D S U U D 2 5ms D S U D D D S U D D 3 10ms D S U U U D D D D D 4 10ms D S U U D D D D D D 5 10ms D S U D D D D D D D 6 5ms D S U U U D S U U D

In Table 1, D represents a downlink subframe, U represents an uplink subframe, and S represents a special subframe. The specific subframe includes three fields: Downlink Pilot TimeSlot (DwPTS), Guard Period (GP), and Uplink Pilot TimeSlot (UpPTS). DwPTS is a time interval reserved for downlink transmission, and UpPTS is a time interval reserved for uplink transmission. Table 2 illustrates the configuration of a specific frame.

Special subframe configuration Normal cyclic prefix in downlink Extended cyclic prefix in downlink DwPTS UpPTS DwPTS UpPTS Normal cyclic prefix in uplink Extended cyclic prefix in uplink Normal cyclic prefix in uplink Extended cyclic prefix in uplink 0 6592 T _s 2192 T _s 2560 T _s 7680 _Ts 2192 T _s 2560 T _s One 19760 T _s 20480 T _s 2 21952 T _s 23040 T _s 3 24144 T _s 25600 T _s 4 26336 T _s 7680 _Ts 4384 T _s
5120 T _s
5 6592 T _s 4384 T _s
5120 T _s
20480 T _s 6 19760 T _s 23040 T _s 7 21952 T _s 12800 T _s 8 24144 T _s - - - 9 13168 T _s - - -

*

개의 부반송파(subcarrier)와

개의 OFDM 심볼로 구성되는 자원격자(resource grid)로 표현될 수 있다. 여기서,

은 하향링크 슬롯에서의 자원블록(resource block, RB)의 개수를 나타내고,

은 UL 슬롯에서의 RB의 개수를 나타낸다.

와

은 DL 전송 대역폭과 UL 전송 대역폭에 각각 의존한다.

은 하향링크 슬롯 내 OFDM 심볼의 개수를 나타내며,

은 UL 슬롯 내 OFDM 심볼의 개수를 나타낸다.

는 하나의 RB를 구성하는 부반송파의 개수를 나타낸다. 2 shows an example of a downlink/uplink (DL/UL) slot structure in a wireless communication system. In particular, FIG. 2 shows the structure of a resource grid of a 3GPP LTE/LTE-A system. There is one resource grid per antenna port. Referring to FIG. 2, a slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. do. An OFDM symbol also means a period of one symbol. Referring to FIG. 2, the signal transmitted in each slot is

*

of subcarriers and

It can be expressed as a resource grid consisting of OFDM symbols. here,

Represents the number of resource blocks (RBs) in a downlink slot,

represents the number of RBs in the UL slot.

and

depends on the DL transmission bandwidth and the UL transmission bandwidth, respectively.

Represents the number of OFDM symbols in a downlink slot,

represents the number of OFDM symbols in the UL slot.

represents the number of subcarriers constituting one RB.

*

개의 부반송파를 포함한다. 부반송파의 유형은 데이터 전송을 위한 데이터 부반송파, 참조신호(reference signal)의 전송 위한 참조신호 부반송파, 가드 밴드(guard band) 및 직류(Direct Current, DC) 성분을 위한 널(null) 부반송파로 나뉠 수 있다. DC 성분을 위한 널 부반송파는 미사용인 채 남겨지는 부반송파로서, OFDM 신호 생성 과정 혹은 주파수 상향변환 과정에서 반송파 주파수(carrier frequency, f0)로 맵핑(mapping)된다. 반송파 주파수는 중심 주파수(center frequency)라고도 한다. The OFDM symbol may be called an OFDM symbol, a single carrier frequency division multiplexing (SC-FDM) symbol, or the like according to a multiple access scheme. The number of OFDM symbols included in one slot may be variously changed according to a channel bandwidth and a cyclic prefix (CP) length. For example, in the case of a normal CP, one slot includes 7 OFDM symbols, but in the case of an extended CP, one slot includes 6 OFDM symbols. In FIG. 2, a subframe in which one slot is composed of 7 OFDM symbols is illustrated for convenience of explanation, but embodiments of the present invention may be applied to subframes having a different number of OFDM symbols in the same manner. Referring to FIG. 2, each OFDM symbol, in the frequency domain,

*

It includes two subcarriers. Types of subcarriers can be divided into data subcarriers for data transmission, reference signal subcarriers for transmission of reference signals, and null subcarriers for guard band and direct current (DC) components. . The null subcarrier for the DC component is a subcarrier that is left unused and is mapped to a carrier frequency (f0) during an OFDM signal generation process or a frequency upconversion process. The carrier frequency is also referred to as the center frequency.

개(예를 들어, 7개)의 연속하는 OFDM 심볼로서 정의되며, 주파수 도메인에서 c개(예를 들어, 12개)의 연속하는 부반송파에 의해 정의된다. 참고로, 하나의 OFDM 심볼과 하나의 부반송파로 구성된 자원을 자원요소(resource element, RE) 혹은 톤(tone)이라고 한다. 따라서, 하나의 RB는

*

개의 자원요소로 구성된다. 자원격자 내 각 자원요소는 일 슬롯 내 인덱스 쌍 (k, 1)에 의해 고유하게 정의될 수 있다. k는 주파수 도메인에서 0부터

*

-1까지 부여되는 인덱스이며, l은 시간 도메인에서 0부터

-1까지 부여되는 인덱스이다. 1 RB is in the time domain

It is defined as (eg, 7) consecutive OFDM symbols, and is defined by c (eg, 12) consecutive subcarriers in the frequency domain. For reference, a resource composed of one OFDM symbol and one subcarrier is called a resource element (RE) or tone. Therefore, one RB is

*

It is composed of resource elements. Each resource element in the resource grid may be uniquely defined by an index pair (k, 1) within one slot. k is from 0 in the frequency domain

*

It is an index given up to -1, and l is from 0 in the time domain.

It is an index given up to -1.

개의 연속하는 동일한 부반송파를 점유하면서, 상기 서브프레임의 2개의 슬롯 각각에 1개씩 위치하는 2개의 RB를 물리자원블록(physical resource block, PRB) 쌍(pair)이라고 한다. PRB 쌍을 구성하는 2개의 RB는 동일한 PRB 번호(혹은, PRB 인덱스(index)라고도 함)를 갖는다. VRB는 자원할당을 위해 도입된 일종의 논리적 자원할당 단위이다. VRB는 PRB와 동일한 크기를 갖는다. VRB를 PRB로 맵핑하는 방식에 따라, VRB는 로컬라이즈(localized) 타입의 VRB와 분산(distributed) 타입의 VRB로 구분된다. 로컬라이즈 타입의 VRB들은 PRB들에 바로 맵핑되어, VRB 번호(VRB 인덱스라고도 함)가 PRB 번호에 바로 대응된다. 즉, n_PRB=n_VRB가 된다. 로컬라이즈 타입의 VRB들에는 0부터

-1순으로 번호가 부여되며,

=

이다. 따라서, 로컬라이즈 맵핑 방식에 의하면, 동일한 VRB 번호를 갖는 VRB가 첫 번째 슬롯과 두 번째 슬롯에서, 동일 PRB 번호의 PRB에 맵핑된다. 반면, 분산 타입의 VRB는 인터리빙을 거쳐 PRB에 맵핑된다. 따라서, 동일한 VRB 번호를 갖는 분산 타입의 VRB는 첫 번째 슬롯과 두 번째 슬롯에서 서로 다른 번호의 PRB에 맵핑될 수 있다. 서브프레임의 두 슬롯에 1개씩 위치하며 동일한 VRB 번호를 갖는 2개의 PRB를 VRB 쌍이라 칭한다. in one subframe

Two RBs, one located in each of the two slots of the subframe, while occupying two consecutive identical subcarriers, are referred to as a physical resource block (PRB) pair. Two RBs constituting a PRB pair have the same PRB number (or also referred to as a PRB index). VRB is a kind of logical resource allocation unit introduced for resource allocation. The VRB has the same size as the PRB. According to a method of mapping VRBs to PRBs, VRBs are divided into localized type VRBs and distributed type VRBs. VRBs of localized type are directly mapped to PRBs, so that a VRB number (also referred to as a VRB index) directly corresponds to a PRB number. That is, n _PRB = n _VRB . For VRBs of localized type, from 0

Numbers are given in the order of -1,

=

am. Accordingly, according to the localized mapping method, VRBs having the same VRB number are mapped to PRBs of the same PRB number in the first slot and the second slot. On the other hand, distributed type VRBs are mapped to PRBs through interleaving. Accordingly, distributed type VRBs having the same VRB number may be mapped to PRBs of different numbers in the first slot and the second slot. Two PRBs located one by one in two slots of a subframe and having the same VRB number are referred to as a VRB pair.

3 illustrates a downlink (DL) subframe structure used in a 3GPP LTE/LTE-A system.

Referring to FIG. 3, a DL subframe is divided into a control region and a data region in the time domain. Referring to FIG. 3, up to 3 (or 4) OFDM symbols located at the front of a first slot of a subframe correspond to a control region to which a control channel is allocated. Hereinafter, a resource region available for PDCCH transmission in a DL subframe is referred to as a PDCCH region. The remaining OFDM symbols other than the OFDM symbol(s) used as the control region correspond to a data region to which a physical downlink shared channel (PDSCH) is allocated. Hereinafter, a resource region available for PDSCH transmission in a DL subframe is referred to as a PDSCH region. Examples of DL control channels used in 3GPP LTE include a Physical Control Format Indicator Channel (PCFICH), a Physical Downlink Control Channel (PDCCH), a Physical Hybrid ARQ Indicator Channel (PHICH), and the like. The PCFICH is transmitted in the first OFDM symbol of a subframe and carries information about the number of OFDM symbols used for transmission of a control channel in the subframe. The PHICH carries a Hybrid Automatic Repeat Request (HARQ) acknowledgment/negative-acknowledgment (ACK/NACK) signal in response to UL transmission.

Control information transmitted through the PDCCH is referred to as downlink control information (DCI). DCI contains resource allocation information and other control information for a UE or group of UEs. For example, the DCI includes transmission format and resource allocation information of a downlink shared channel (DL-SCH), transmission format and resource allocation information of a UL shared channel (UL-SCH), paging channel (paging paging information on channel (PCH), system information on DL-SCH, resource allocation information of upper layer control messages such as random access responses transmitted on PDSCH, transmission power control commands for individual UEs in a UE group ( Transmit Control Command Set), transmit power control command, activation indication information of Voice over IP (VoIP), downlink assignment index (DAI), and the like. The transmit format and resource allocation information of the DL shared channel (downlink shared channel, DL-SCH) is also called DL scheduling information or DL grant, and The transmission format and resource allocation information is also called UL scheduling information or UL grant. The DCI carried by one PDCCH has different sizes and uses depending on the DCI format, and may vary according to the coding rate. In the current 3GPP LTE system, various formats such as formats 0 and 4 for uplink and formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, 3, and 3A for downlink are defined. Hopping flag, RB allocation, modulation coding scheme (MCS), redundancy version (RV), new data indicator (NDI), transmit power control (TPC), cyclic shift DMRS (cyclic) control information such as shift demodulation reference signal), UL index, channel quality information (CQI) request, DL assignment index, HARQ process number, transmitted precoding matrix indicator (TPMI), and precoding matrix indicator (PMI) information The selected combination is transmitted to the UE as downlink control information.

In general, a DCI format that can be transmitted to the UE varies according to a transmission mode (TM) configured in the UE. In other words, not all DCI formats can be used for a UE configured for a specific transmission mode, but only certain DCI format(s) corresponding to the specific transmission mode.

The PDCCH is transmitted on an aggregation of one or a plurality of contiguous control channel elements (CCEs). CCE is a logical allocation unit used to provide a PDCCH with a coding rate based on radio channel conditions. A CCE corresponds to a plurality of resource element groups (REGs). For example, one CCE corresponds to 9 REGs and one REG corresponds to 4 REs. In the case of the 3GPP LTE system, a CCE set in which a PDCCH can be located is defined for each UE. A CCE set in which a UE can discover its own PDCCH is referred to as a PDCCH search space, or simply a search space (SS). An individual resource on which a PDCCH can be transmitted within a search space is referred to as a PDCCH candidate. A collection of PDCCH candidates to be monitored by the UE is defined as a search space. In the 3GPP LTE/LTE-A system, a search space for each DCI format may have a different size, and a dedicated search space and a common search space are defined. A dedicated search space is a UE-specific search space and is configured for each individual UE. A common search space is configured for multiple UEs. An aggregation level defining the search space is as follows.

Search Space S _K ^(L)
Number of PDCCH candidates M ^(L) Type Aggregation Level L Size [in CCEs] UE-specific


One 6 6 2 12 6 4 8 2 8 16 2 Common
4 16 4 8 16 2

One PDCCH candidate corresponds to 1, 2, 4 or 8 CCEs according to the CCE aggregation level. The eNB transmits the actual PDCCH (DCI) on any PDCCH candidate in the search space, and the UE monitors the search space to find the PDCCH (DCI). Here, monitoring means attempting decoding of each PDCCH in a corresponding search space according to all monitored DCI formats. The UE may detect its own PDCCH by monitoring the plurality of PDCCHs. Basically, since the UE does not know where its PDCCH is transmitted, it tries to decode the PDCCH for all PDCCHs of the DCI format in every subframe until it detects a PDCCH with its own identifier. This process is blind detection ( It is called blind detection (blind decoding, BD). The eNB can transmit data for a UE or a group of UEs through a data area. Data transmitted through the data area is also referred to as user data. For transmission of user data, a Physical Downlink Shared CHannel (PDSCH) may be allocated to the data area. A paging channel (PCH) and a downlink-shared channel (DL-SCH) are transmitted through the PDSCH. The UE can read data transmitted through the PDSCH by decoding control information transmitted through the PDCCH. Information indicating which UE or UE group the PDSCH data is transmitted to and how the UE or UE group should receive and decode the PDSCH data is included in the PDCCH and transmitted. For example, a specific PDCCH is masked by a cyclic redundancy check (CRC) with a Radio Network Temporary Identity (RNTI) of "A", a radio resource (eg, frequency location) of "B" and transmission of "C" It is assumed that information on data transmitted using format information (eg, transport block size, modulation scheme, coding information, etc.) is transmitted through a specific DL subframe. The UE monitors the PDCCH using its own RNTI information, and the UE with the RNTI of "A" detects the PDCCH and uses the received PDCCH information to detect the PDSCH indicated by "B" and "C" receive

For demodulation of the signal received by the UE from the eNB, a reference signal (RS) to be compared with the data signal is required. The reference signal means a signal of a predefined special waveform transmitted from the eNB to the UE or from the UE to the eNB, known to the eNB and the UE, and is also called a pilot. Reference signals are divided into a cell-specific RS shared by all UEs in a cell and a demodulation RS (DM RS) dedicated to a specific UE. A DM RS transmitted by an eNB to demodulate downlink data for a specific UE is also specifically referred to as a UE-specific RS. In downlink, DM RS and CRS may be transmitted together, but only one of them may be transmitted. However, when only DM RS is transmitted without CRS in downlink, since DM RS transmitted by applying the same precoder as data can be used only for demodulation purposes, an RS for channel measurement must be provided separately. For example, in 3GPP LTE(-A), CSI-RS, which is an additional RS for measurement, is transmitted to the UE so that the UE can measure channel state information. Unlike the CRS transmitted every subframe, the CSI-RS is transmitted every predetermined transmission period consisting of a plurality of subframes based on the fact that the channel state does not have a relatively large change over time.

4 shows an example of an uplink (UL) subframe structure used in a 3GPP LTE/LTE-A system.

Referring to FIG. 4, a UL subframe may be divided into a control region and a data region in the frequency domain. One or several physical uplink control channels (PUCCHs) may be allocated to the control region to carry uplink control information (UCI). One or several physical uplink shared channels (PUSCHs) may be allocated to the data region of the UL subframe to carry user data.

In the UL subframe, subcarriers that are far from DC (Direct Current) subcarriers are used as a control region. In other words, subcarriers positioned at both ends of the UL transmission bandwidth are allocated to transmission of uplink control information. The DC subcarrier is a component that remains unused for signal transmission and is mapped to the carrier frequency f0 in a frequency upconversion process. A PUCCH for one UE is allocated to a pair of RBs belonging to resources operating on one carrier frequency in one subframe, and the RBs belonging to the RB pair occupy different subcarriers in two slots. The PUCCH allocated in this way is expressed as frequency hopping at a slot boundary between a pair of RBs allocated to the PUCCH. However, when frequency hopping is not applied, the RB pair occupies the same subcarrier.

PUCCH may be used to transmit the following control information.

- SR (Scheduling Request): Information used to request uplink UL-SCH resources. It is transmitted using the On-Off Keying (OOK) method.

- HARQ-ACK: This is a response to a PDCCH and/or a downlink data packet (eg, codeword) on the PDSCH. Indicates whether the PDCCH or PDSCH has been successfully received. In response to a single downlink codeword, 1 bit of HARQ-ACK is transmitted, and in response to two downlink codewords, 2 bits of HARQ-ACK are transmitted. The HARQ-ACK response includes positive ACK (simply ACK), negative ACK (hereinafter NACK), DTX (Discontinuous Transmission) or NACK/DTX. Here, the term HARQ-ACK is used interchangeably with HARQ ACK/NACK and ACK/NACK.

- CSI (Channel State Information): This is feedback information for a downlink channel. Multiple Input Multiple Output (MIMO)-related feedback information includes a Rank Indicator (RI) and a Precoding Matrix Indicator (PMI).

The amount of uplink control information (UCI) that the UE can transmit in a subframe depends on the number of SC-FDMAs available for transmission of control information. SC-FDMA available for UCI refers to SC-FDMA symbols remaining after excluding SC-FDMA symbols for reference signal transmission in a subframe, and in the case of a subframe configured with SRS (Sounding Reference Signal), the last SC of the subframe -FDMA symbols are also excluded. The reference signal is used for coherent detection of PUCCH. PUCCH supports various formats according to transmitted information.

Table 4 shows the mapping relationship between PUCCH format and UCI in LTE/LTE-A system.

PUCCH format Modulation scheme Number of bits per subframe Usage Etc. One N/A N/A (exist or absent) SR (Scheduling Request) 1a BPSK One ACK/NACK or
SR + ACK/NACK One codeword 1b QPSK 2 ACK/NACK or
SR + ACK/NACK Two codewords 2 QPSK 20 CQI/PMI/RI Joint coding ACK/NACK (extended CP) 2a QPSK+BPSK 21 CQI/PMI/RI + ACK/NACK Normal CP only 2b QPSK+QPSK 22 CQI/PMI/RI + ACK/NACK Normal CP only 3 QPSK 48 ACK/NACK or
SR + ACK/NACK or
CQI/PMI/RI + ACK/NACK

Referring to Table 4, the PUCCH format 1 series is mainly used to transmit ACK/NACK information, and the PUCCH format 2 series is mainly used to carry channel state information (CSI) such as CQI/PMI/RI. , the PUCCH format 3 series is mainly used to transmit ACK/NACK information.

Reference Signal (RS)

When a packet is transmitted in a wireless communication system, since the transmitted packet is transmitted through a wireless channel, signal distortion may occur during the transmission process. In order to correctly receive the distorted signal at the receiving side, the distortion must be corrected in the received signal using channel information. In order to find channel information, a method in which a signal known to both the transmitting side and the receiving side is transmitted and the channel information is found with a degree of distortion when the signal is received through a channel is mainly used. The signal is referred to as a pilot signal or a reference signal.

When data is transmitted/received using multiple antennas, a correct signal can be received by knowing the channel condition between each transmit antenna and receive antenna. Therefore, a separate reference signal must exist for each transmit antenna, more specifically for each antenna port (antenna port).

Reference signals can be divided into uplink reference signals and downlink reference signals. As an uplink reference signal in the current LTE system,

i) Demodulation-Reference Signal (DM-RS) for channel estimation for coherent demodulation of information transmitted through PUSCH and PUCCH

ii) There is a Sounding Reference Signal (SRS) for the base station and the network to measure uplink channel quality in a different frequency.

On the other hand, in the downlink reference signal,

i) Cell-specific reference signal (CRS) shared by all terminals in the cell

ii) UE-specific reference signal for specific UE only

iii) When PDSCH is transmitted, transmitted for coherent demodulation (DeModulation-Reference Signal, DM-RS)

iv) Channel State Information-Reference Signal (CSI-RS) for transmitting channel state information (CSI) when downlink DMRS is transmitted

v) MBSFN Reference Signal transmitted for coherent demodulation of a signal transmitted in MBSFN (Multimedia Broadcast Single Frequency Network) mode

vi) There is a positioning reference signal used to estimate the geographic location information of the terminal.

Reference signals can be largely classified into two types according to their purpose. There is a reference signal for the purpose of obtaining channel information and a reference signal used for data demodulation. Since the former has a purpose for allowing the UE to acquire downlink channel information, it must be transmitted over a wide band, and even a UE that does not receive downlink data in a specific subframe must receive the reference signal. It is also used in situations such as handover. The latter is a reference signal that the base station sends along with a corresponding resource when sending downlink, and the terminal can demodulate data by measuring the channel by receiving the reference signal. This reference signal must be transmitted in an area where data is transmitted.

CSI reporting

In the 3GPP LTE (-A) system, the user equipment (UE) is defined to report channel state information (CSI) to the base station (BS), and the channel state information (CSI) is a radio signal formed between the UE and the antenna port. It collectively refers to information that can indicate the quality of a channel (or referred to as a link). For example, a rank indicator (RI), a precoding matrix indicator (PMI), a channel quality indicator (CQI), and the like correspond to this. Here, RI represents rank information of a channel, which means the number of streams that the UE receives through the same time-frequency resource. Since this value is determined depending on the long-term fading of the channel, it is fed back from the UE to the BS with a period usually longer than that of the PMI and CQI. PMI is a value reflecting channel spatial characteristics and represents a precoding index preferred by the UE based on a metric such as SINR. CQI is a value representing the strength of a channel and generally means a received SINR that can be obtained when a BS uses PMI.

Based on the measurement of the radio channel, the UE calculates a preferred PMI and RI that can derive the optimal or highest transmission rate if used by the BS under the current channel conditions, and feeds the calculated PMI and RI back to the BS do. Here, CQI refers to a modulation and coding scheme that provides an acceptable packet error probability for the fed back PMI/RI.

On the other hand, in an LTE-A system that is expected to include more precise MU-MIMO and explicit CoMP operations, the current CSI feedback is defined in LTE and therefore does not sufficiently support those newly introduced operations. As the requirements for CSI feedback accuracy become increasingly stringent to achieve sufficient MU-MIMO or CoMP throughput gain, the long term/wideband PMI (W ₁ ) and short term ( Short term)/subband PMI (W ₂ ), agreed to be composed of two. In other words, the final PMI is expressed as a function of W ₁ and W ₂ . For example, the final PMI W can be defined as: W=W ₁ *W ₂ or W=W ₂ *W ₁ . Therefore, CSI in LTE-A will consist of RI, W ₁ , W ₂ and CQI.

Uplink channels used for CSI transmission in the 3GPP LTE (-A) system are shown in Table 5 below.

scheduling method Periodic CSI Transmission Aperiodic CSI Transmission frequency non-selective PUCCH - frequency selective PUCCH PUSCH

Referring to Table 5, CSI can be transmitted using a Physical Uplink Control Channel (PUCCH) at a period determined by a higher layer, and aperiodically according to the needs of the scheduler (Physical Uplink Shared Channel). It can be transmitted using Shared Channel, PUSCH). The case in which CSI is transmitted through the PUSCH is possible only in the case of frequency selective scheduling and aperiodic CSI transmission. Hereinafter, a CSI transmission method according to a scheduling method and periodicity will be described. 1) CQI/PMI/RI transmission through PUSCH after receiving a CSI transmission request control signal (CSI request)

A control signal requesting transmission of CSI may be included in a PUSCH scheduling control signal (UL Grant) transmitted as a PDCCH signal. The following table shows UE modes when transmitting CQI, PMI, and RI through PUSCH.

PMI Feedback Type
No PMI Single PMI Multiple PMIs PUSCH CQI Feedback Type

Wideband
(Wideband CQI) Mode 1-2

RI

1st wideband CQI(4bit)
2nd wideband CQI(4bit)
if RI>1

N*Subband PMI(4bit)
(N is the total # of subbands)
(if 8Tx Ant, N*subband W2 + wideband W1) UE selected
(Subband CQI) Mode 2-0

RI (only for open-loop SM)

1st wideband CQI(4bit) + Best-M CQI(2bit)
(Best-M CQI: average CQI for M selected SBs among a total of N SBs)
Best-M index (L bit) Mode 2-2

RI

1st wideband CQI(4bit) + Best-M CQI(2bit)
2nd wideband CQI(4bit) + Best-M CQI(2bit) if RI>1
Best-M index (L bit)

Wideband PMI(4bit)+ Best-M PMI(4bit)
(if 8Tx Ant, wideband W2 + Best-M W2 + wideband W1) Higher layer-configured
(Subband CQI) Mode 3-0

RI (only for open-loop SM)

1st wideband CQI(4bit)+N*subbandCQI(2bit) Mode 3-1

RI

1st wideband CQI(4bit)+ N*subbandCQI(2bit)
2nd wideband CQI(4bit)+ N*subbandCQI(2bit) if RI>1

Wideband PMI (4bit)
(if 8Tx Ant, wideband W2 + wideband W1) Mode 3-2

RI

1st wideband CQI(4bit)+ N*subbandCQI(2bit)
2nd wideband CQI(4bit)+ N*subbandCQI(2bit) if RI>1

N*Subband PMI(4bit)
(N is the total # of subbands)
(if 8Tx Ant, N*subband W2 + wideband W1)

The transmission mode of Table 6 is selected in a higher layer, and CQI/PMI/RI are all transmitted in the same PUSCH subframe. Hereinafter, an uplink transmission method of a UE according to each mode will be described. Mode 1-2 (Mode 1-2) selects a precoding matrix for each subband on the assumption that data is transmitted through only the subband. indicates the case of The UE generates a CQI by assuming a precoding matrix selected for the system band or the entire band (set S) designated by a higher layer. In mode 1-2, the UE may transmit the CQI and the PMI value of each subband. In this case, the size of each subband may vary according to the size of the system band.

A UE in mode 2-0 (Mode 2-0) may select M subbands preferred for a system band or a set band designated by an upper layer (set S). The UE may generate one CQI value under the assumption that data is transmitted on the selected M subbands. It is preferable that the UE additionally reports one wideband CQI (CQI) value for the system band or set S. When there are a plurality of codewords for the selected M subbands, the UE defines a CQI value for each codeword in a differential format.

At this time, the differential CQI value is determined as a difference between an index corresponding to CQI values for the selected M subbands and a wideband CQI (WB-CQI) index.

The UE in mode 2-0 transmits information on the location of the selected M subbands, one CQI value for the selected M subbands, and a CQI value generated for all bands or a designated band (set S) to the BS. can In this case, the subband size and M value may vary depending on the size of the system band.

Under the assumption that the UE in Mode 2-2 transmits data through M preferred subbands, it simultaneously selects the positions of the M preferred subbands and a single precoding matrix for the M preferred subbands. can In this case, CQI values for M preferred subbands are defined for each codeword. In addition, the UE additionally generates a wideband CQI (wideband CQI) value for a system band or a designated band (set S).

The UE in mode 2-2 receives information on locations of M preferred subbands, one CQI value for the selected M subbands, a single PMI for the M preferred subbands, a wideband PMI, and a wideband CQI value. Can be sent to BS. In this case, the subband size and M value may vary according to the size of the system band.

A UE in Mode 3-0 generates a wideband CQI value. The UE generates a CQI value for each subband under the assumption that data is transmitted through each subband. At this time, even if RI > 1, the CQI value represents only the CQI value for the first codeword.

The UE in Mode 3-1 generates a single precoding matrix for a system band or a designated band (set S). The UE assumes a single precoding matrix previously generated for each subband and generates a subband CQI for each codeword. Also, the UE may assume a single precoding matrix and generate a wideband CQI. The CQI value of each subband may be expressed in a differential format. The subband CQI value is calculated as a difference between the subband CQI index and the wideband CQI index. In this case, the size of the subband may vary according to the size of the system band.

Compared to Mode 3-1, a UE in Mode 3-2 generates a precoding matrix for each subband instead of a single precoding matrix for the entire band.

2) Periodic CQI/PMI/RI transmission through PUCCH

The UE may periodically transmit CSI (e.g. CQI/PMI/precoding type indicator (PTI) and/or RI information) to the BS through PUCCH. If the UE receives a control signal to transmit user data, the UE may transmit the CQI through the PUCCH. Even if the control signal is transmitted through the PUSCH, CQI/PMI/PTI/RI may be transmitted by one of the modes defined in the following table.

PMI feedback type No PMI single PMI PUCCH CQI feedback type broadband
(Wideband CQI) Mode 1-0 Mode 1-1 Select UE
(subband CQI) Mode 2-0 Mode 2-1

A UE may have a transmission mode as shown in Table 7. Referring to Table 7, in the case of Mode 2-0 and Mode 2-1, a bandwidth part (BP: Bandwidth Part) is a set of subbands continuously located in the frequency domain. It can cover all system bands or designated bands (set S). In Table 9, the size of each subband, the size of BPs, and the number of BPs may vary depending on the size of the system band. In addition, the UE transmits CQIs for each BP in ascending order in the frequency domain so as to cover the system band or designated band (set S). Depending on the transmission combination of CQI/PMI/PTI/RI, the UE transmits the following PUCCH can have a type.

i) Type 1: Subband CQI (SB-CQI) of Mode 2-0 and Mode 2-1 is transmitted.

ii) Type 1a: Subband CQI and second PMI are transmitted

iii) Type 2, Type 2b, Type 2c: Wideband CQI and PMI (WB-CQI/PMI) are transmitted.

iv) Type 2a: Wideband PMI is transmitted.

v) Type 3: RI is transmitted.

vi) Type 4: Wideband CQI is transmitted.

vii) Type 5: RI and wideband PMI are transmitted.

viii) Type 6: RI and PTI are transmitted.

When the UE transmits RI and wideband CQI/PMI, the CQI/PMI is transmitted in subframes having different periods and offsets. In addition, when RI and wideband CQI/PMI are to be transmitted in the same subframe, CQI/PMI is not transmitted.

Downlink assignment indicator (DAI) in LTE

The FDD scheme is a scheme for transmission and reception by distinguishing downlink (DL) and uplink (UL) for each independent frequency band. Therefore, when the base station transmits the PDSCH in the DL band, the terminal performs an ACK/NACK response indicating whether or not intact data is received through the PUCCH of the UL band corresponding to the DL band after a specific time. Accordingly, the DL and the UL operate in a one-to-one correspondence.

Specifically, in the example of the existing 3GPP LTE system, control information for downlink data transmission of the base station is delivered to the terminal through the PDCCH, and the terminal receiving data scheduled for itself through the PDCCH through the PDSCH transmits uplink control information ACK/NACK is transmitted through PUCCH, which is a channel for transmitting. At this time, in general, the PUCCH for ACK/NACK transmission is not pre-allocated to each terminal, but a structure in which a plurality of terminals in a cell divide and use a plurality of PUCCHs at each point in time, and receive downlink data at any point in time A PUCCH on which one UE transmits ACK/NACK uses a PUCCH corresponding to a PDCCH on which the UE receives scheduling information for downlink data. More specifically, the region in which the PDCCH of each downlink subframe is transmitted is composed of a plurality of control channel elements (CCEs), and the PDCCH transmitted to one UE in an arbitrary subframe is among the CCEs constituting the PDCCH region of the subframe. It is composed of one or more control channel elements (CCEs). In addition, resources capable of transmitting a plurality of PUCCHs exist in an area where PUCCHs of each uplink subframe are transmitted. At this time, the UE transmits ACK/NACK through a PUCCH corresponding to an index corresponding to an index of a specific (ie, first) CCE among CCEs constituting the PDCCH received by the UE. 5 shows the structure described above.

In FIG. 5, each square in a DL CC represents a CCE, and each square in a UL CC represents a PUCCH. As shown in FIG. 5, if a UE obtains PDSCH-related information through a PDCCH composed of CCEs 4, 5, and 6 and receives the PDSCH, it receives an ACK through PUCCH 4 corresponding to CCE 4, which is the first CCE constituting the PDCCH. Send /NACK.

Unlike FDD, the TDD scheme divides and uses the same frequency band into a DL subframe and a UL subframe on the time axis. Therefore, in case of asymmetric data traffic situation in DL/UL, many DL subframes or UL subframes are allocated. In this case, unlike FDD, there is a case where DL and UL subframes do not correspond one-to-one. In particular, when the number of DL subframes is greater than the number of UL subframes, a situation arises in which ACK/NACK responses to a plurality of PDSCHs transmitted in a plurality of subframes must be processed in one subframe.

In this way, when a plurality of PDSCHs are transmitted to one UE in a plurality of DL subframes, the base station transmits a plurality of PDCCHs one by one for each PDSCH. At this time, the UE may transmit ACK/NACK through one PUCCH through one UL subframe for the received plurality of PDSCHs. A method of transmitting one ACK/NACK for a plurality of PDSCHs can be roughly divided into two methods as follows.

1) Bundled ACK/NACK transmission (ACK/NACK bundling): When the UE successfully decodes all received PDSCHs, it transmits one ACK through one PUCCH. In other cases, NACK is transmitted.

2) PUCCH selective transmission: A UE receiving a plurality of PDSCHs occupies a plurality of PUCCHs that it can use for ACK/NACK transmission in an arbitrary manner, and selects one of the plurality of PUCCHs occupied in this way to transmit ACK/NACK A plurality of ACKs/NACKs are transmitted using a combination of transmission and modulated/encoded contents of the PUCCH selected and transmitted.

The following problems occur when a terminal transmits an ACK/NACK signal to a base station through the above methods.

- If the UE misses part of the PDCCH sent by the base station during several subframe intervals, the UE cannot know that the PDSCH corresponding to the missed PDCCH has been transmitted to itself, so an error may occur in ACK/NACK generation.

In order to solve this error, in the TDD system, the number of PDSCHs to be transmitted in ACK/NACK resources of one UL subframe is counted and notified by including a downlink assignment index (DAI) in the PDCCH. For example, when one UL subframe corresponds to three DL subframes, indexes are sequentially assigned to PDSCHs transmitted in three DL subframes (i.e., sequentially counted) to schedule PDSCHs It is carried on the PDCCH, and the terminal can see the DAI information in the PDCCH to know whether the previous PDCCH has been properly received.

In the first example of FIG. 6, when the UE misses the 2nd PDCCH, since the DAI of the 3rd PDCCH, which is the last PDCCH, and the number of PDCCHs received so far are different, it recognizes that it has missed the 2nd PDCCH and ACK accordingly /NACK is shown. On the other hand, when the last PDCCH is missed as in the second example, the UE cannot recognize that the last PDCCH has been missed because the DAI and the number of PDCCHs received so far match. There is room. At this time, since the ACK/NACK information is transmitted through a PUCCH resource corresponding to DAI=2 rather than a PUCCH resource corresponding to DAI=3, the base station can determine that the UE missed the PDCCH including DAI=3.

In this case, DAI according to the above description means DL DAI, and is included in DL control information (eg, PDCCH, EPDCCH) indicating PDSCH transmission or DL SPS release and transmitted to the terminal. When the base station triggers UL transmission of the terminal at the time of transmitting the ACK/NACK, the base station may transmit the UL DAI including the DCI indicating the UL grant. The UL DAI means the accumulated number of PDSCHs for ACK/NACK transmission within a certain interval or PDCCH/EPDCCHs indicating SPS release, or the number of DL subframes for ACK/NACK transmission in the case of CA. In the case of piggybacking ACK/NACK to the PUSCH in the example of FIG. 6 through the UL DAI, the base station can inform the UL grant of DAI=3 to let the terminal know that the second PDCCH has been missed.

In the present specification, when a massive carrier aggregation (CA) technique supporting aggregation of a plurality of component carriers (CCs) is supported in a wireless communication system, uplink control information (UCI) of the CCs is used as an uplink (UL) data channel, For example, a method of adaptively changing a UCI resource (or a UCI payload size), which is a resource allocated to perform piggyback on a physical uplink shared channel (PUSCH), is proposed.

In advanced wireless communication systems such as 3GPP LTE, the characteristics of information in uplink are divided into UCI and data, and PUCCH, a channel for transmitting UCI, and PUSCH, a channel for transmitting data, are designed and used according to the characteristics of each information do. However, when the UE is not configured to simultaneously transmit the PUCCH and the PUSCH, if PUSCH transmission exists at the time of UCI transmission, the UE piggybacks and transmits the UCI to the PUSCH. 7 is a general CP and when UCI is transmitted on a PUSCH, UCI details such as ACK/NACK, RI (rank indicator), CQI (channel quality indicator)/PMI (precoding matrix indicator), etc. are mapped on the resource domain. shows 7 is an example of a case in which PUSCH resources are allocated to 1 RB in an LTE system according to an embodiment of the present invention, and the horizontal axis represents a single carrier frequency division multiple access (SC-FDMA) symbol, and the vertical axis represents a subcarrier. In this case, the time index of the SC-FDMA symbol increases from left to right, and the frequency index of the subcarrier increases from top to bottom. In addition, regions are represented by different hatching for each type of UCI, and numbers within the same region indicate the mapping order of coded symbols.

At this time, CQI/PMI performs mapping without considering the resource location of ACK/NACK. Therefore, if ACK/NACK occupies the entire SC-FDMA symbol, the CQI/PMI at the corresponding location in FIG. 5 is punctured. .

In FIG. 7, as the proportion of resources (hereinafter referred to as "UCI resources") to which UCI is allocated within PUSCH resources increases, resources for transmitting data decrease, and in terms of efficiently utilizing resources, the UCI resources guarantee performance. It is desirable to allocate as little as possible. In particular, among the types of UCI, it may be desirable to report whether HARQ-ACK is an ACK or NACK for a PDSCH on which downlink (DL) scheduling is actually performed, in view of the efficiency of resource utilization. However, in the case of the above operation, the base station performed DL scheduling on a specific PDSCH, but the terminal determined that the corresponding TB was not transmitted due to DCI (downlink control information) detection failure, etc., and the HARQ-ACK configuration reported by the terminal ( For example, a problem in which the HARQ-ACK collection for PDSCH detected by the UE) and the HARQ-ACK configuration expected by the base station (eg, HARQ-ACK collection for PDSCH actually transmitted) are different may occur. As an example, assume that a base station configures two DL CCs (eg, CC ₁ and CC ₂ ) for a terminal by applying a CA technique, and the terminal transmits an HARQ-ACK for a PDSCH detected by the base station. Then, even if the base station transmits PDSCHs on CC ₁ and CC ₂ , the UE only succeeds in detecting the PDSCH on CC ₂ and reports HARQ-ACK for the PDSCH transmitted on CC ₂ . On the other hand, the base station expects two HARQ-ACKs for two PDSCHs, and even if it knows that one HARQ-ACK has been reported by a method such as BD (blind detection), it can determine which CC the corresponding HARQ-ACK was transmitted from. I don't know if it's for PDSCH.

In order to solve the above problem, the LTE system configures / sets HARQ-ACK feedback (eg, codebook or payload size) for all potential PDSCHs on which DL scheduling can be performed for the UE, and the UE configures all of the above HARQ-ACK for PDSCH is transmitted. However, when there is no data transmission in a specific PDSCH or when the UE fails to detect, DTX is defined and reported as HARQ-ACK. At this time, the DTX may be bundled with NACK and reported as one state of NACK/DTX. For example, when the CA technique is applied in the LTE system and HARQ-ACK is transmitted through PUSCH resources, the base station is designed to report HARQ-ACK based on PDSCH transmittable on all CCs configured for the terminal. On the other hand, in the LTE Rel-10/11/12 system, the CA technology for transmitting downlink data by combining up to five CCs to the terminal was considered, but in LTE Rel-13, the amount of DL traffic that has recently rapidly increased A massive CA technique that expands the number of CCs up to 32 (or 16) for the purpose of supporting is being discussed. When the number of CCs that can be set to the terminal increases significantly due to the large-scale CA scheme, HARQ-ACK for the PDSCH transmittable on all CCs set to the terminal in the UCI piggyback process within the PUSCH resource, as in the conventional LTE system. If s are reported, the proportion of UCI resources in PUSCH resources increases, reducing the resource area for data transmission. In addition, as most of the CCs to be utilized in the plurality of large-scale CA schemes are expected to be composed of resources of unlicensed bands in which PDSCH transmission is opportunistically generated according to channel sensing results, the inefficiency will be further aggravated. It is expected that

Therefore, the present invention is a method for adaptively changing the UCI resource as needed when performing UCI piggyback within the PUSCH resource when supporting a large-scale CA technique. We propose a method of transmitting to UCI resources differentiated from each other for each CC group, and (2) a method of directly instructing a CG to be UCI piggybacked by the base station. Hereinafter, an operation in an LTE system will be described as a specific embodiment of the present invention, but the present invention can be applied to any wireless communication system.

Individual UCI coding/resource mapping for each CG

- UCI resources by CG

According to a specific embodiment of the present invention, when a UE performs UCI piggyback on a PUSCH resource, information on one or more CGs composed of a plurality of CCs is directly signaled from the base station to the UE, or cell index and number of cells are transmitted. Based on this, it is set in advance according to specific rules, and the terminal combines UCIs corresponding to all CCs in the corresponding CG for each CG, and then applies separate coding (eg, RM (reed-muller) code) for each CG to each A method for deriving UCI resources for each CG is proposed. In this case, the UCI resource may mean coded bits for UCI transmission, a plurality of coded symbols, or a plurality of resource elements (REs), and different (or differentiated) UCI resources are configured/allocated for each CG. It can be. In the present invention, individual coding is applied to each CG means that the input payload of the same encoder does not consist of a combination of UCIs corresponding to a plurality of different CGs (in other words, the input payload of each encoder A load consists only of UCIs corresponding to the same CG).

Considering the case of HARQ-ACK, preferably, the UCI payload size or UCI resource may be determined by reflecting actual DL scheduling of a PDSCH transmittable in an individual CC. Although the above scheme enables flexible UCI resource allocation, it may be accompanied by an increase in signaling overhead or an increase in complexity in implementing the base station for recognizing the flexible UCI resource change between the terminal and the base station. For example, when the base station indicates CCs that are HARQ-ACK transmission targets, a downlink assignment index (DAI) of the CC domain may be added to a DCI triggering a PUSCH resource. That is, the DAI may indicate whether DL scheduling is performed for up to 32 CCs, and in this case, signaling overhead may be greatly increased. Therefore, in the present invention, in terms of mitigating the above problem, the concept of CG is assumed as the minimum unit capable of adaptively changing UCI resources, and the UE does not arbitrarily change the UCI resources for each CG, and all CCs belonging to the corresponding CG are not arbitrarily changed. We propose a method of calculating based on the UCI corresponding to . In the present invention, a CG may be composed of one or more cells.

- How to classify and allocate UCI resources for each CG

1. Logical resource area

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource, an index is assigned to REs in a time/frequency resource region within the PUSCH resource, and a virtual logical resource following the index A method of defining a region and classifying and allocating UCI resources for each CG within the logical resource region is proposed. In this case, the RE having the i-th index in the logical resource region may be determined as an RE to which the i-th coded symbol for UCI is allocated among the REs of the time/frequency resource region in the PUSCH resource.

As an example, in the case of HARQ-ACK, indexes from 0 to 21 are assigned to REs transmittable for HARQ-ACK within a PUSCH resource in FIG. 7, and a logical resource region according to the index can be considered as shown in FIG. 8.

Here, although the indexing shown in FIG. 7 is assumed in FIG. 8 for convenience, the indexing method between the base station and the terminal may be applied up to the maximum number of REs allocable for UCI or up to a specific number of REs set by the base station. That is, the UE configures a logical resource region for UCI resource allocation by assuming all the number of REs that can be allocated for a specific UCI in PUSCH resources, or the UCI payload size set by the base station through higher layer signals, etc. The logical resource region may be configured in consideration of the number of REs calculated on the assumption. For example, in the case of HARQ-ACK, when one resource block (RB) is allocated as a PUSCH resource as shown in FIG. 7, a logical resource region can be defined by giving an index for 48REs corresponding to up to 4 symbols.

1.1 Individual UCI resource setting and UCI allocation plan for each CG in proportion to the UCI payload size for each CG

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource and a logical resource region composed of ordered REs is defined as described above, a UCI page for all CGs A UCI _resource (or N _tot coded symbols) composed of N _tot REs is determined based on B _tot bits, which is the load, and the UCI resource for the k th CG is the UCI payload of the k th CG. We propose a method of defining individual UCI resources for each CG by distributing them in proportion to B _k bits. That is, if there are a total of K CGs and the individual UCI resources for the k-th CG are N _k , the individual UCI resources for each CG do not have overlapping resources (eg, REs) within the N _tot REs and N ₀ + N ₁ + . + N _K-1 ≤ N _tot .

For example, in the case of HARQ-ACK, when a PUSCH resource transmits one transport block (TB) in an LTE system according to an embodiment of the present invention, a UCI resource for an HARQ-ACK payload size of 0 bits, that is, a coded symbol The number Q' can be determined by the following equation.

는 할당된 PUSCH 자원의 주파수 축 서브캐리어 수를,

는 PUSCH 자원이 할당된 SC-FDMA 심볼 수를, K_r은 r번째 코드 블록에서 전송되는 비트 수를,

는 설계 파라미터를 의미하며,

는 올림(ceiling) 기호를 의미한다.here,

Is the number of subcarriers in the frequency axis of the allocated PUSCH resource,

is the number of SC-FDMA symbols to which PUSCH resources are allocated, K _r is the number of bits transmitted in the r-th code block,

is the design parameter,

means a ceiling sign.

Using the above equation, the number of coded symbols N _tot when the UCI payload size value B _tot bits for all CCs (or CGs) is substituted for the value O, can be calculated. Then, for the UCI resource for the k-th CG, when the payload size of the corresponding CG is B _k bits, the N _tot REs can be calculated as in the following equation in proportion to the UCI payload size B _k bits of the corresponding CG. there is.

At this time, the UCI for each CG is generated in the form of a mother code to which a coding technique such as RM coding is applied, and if the bits of the mother code are smaller than the bits that can be transmitted in the individual UCI resource, cyclic repetition ( Circular repetition is performed, and if it is large, the latter part of the parent code is truncated and rate matched, and transmitted in the individual UCI resource.

1.2 Sequential Allocation in Logical Resource Zones

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource and a logical resource region composed of sequential REs is defined as in the above method, priority information for the plurality of CGs ( or order information) is signaled directly from the base station to the terminal or is defined in advance by a specific rule based on the CG index, etc., and the terminal allocates UCI resources for each CG according to the priority (or order) between the CGs in the logical resource area. A method of sequentially allocating to is described.

That is, the UCI resources for the CG having the n+1 th priority (or order) are allocated from the RE after the UCI resource allocation for the CG having the n th priority (or order) is finished. At this time, if L REs are required to allocate UCI resources for the specific m-th CG, and the number of remaining REs due to the sequential allocation is less than L or there are no remaining REs, the UE receives the UCI for the m-th CG. Resources may not be allocated.

In order to more clearly explain the operation of the present invention, a method of deriving a UCI resource (eg, a plurality of REs or a plurality of coded symbols or coded bits for UCI transmission) of a specific CG by the following two methods define

- First method: Based on the UCI payload size B _tot bits for all CGs, all UCI resources in the PUSCH resource are derived as N _tot REs or the number of coded symbols, and then the UCI payload size B _k bits of the kth CG A method of determining UCI resources for each CG so that CGs do not overlap with each other by distributing the Ntot in proportion to .

(Example) In case of transmitting 1 TB in LTE system

First, based on the total UCI payload size B _tot bits, the number N _tot of all coded symbols in the PUSCH resource can be derived as shown in the following equation.

는 할당된 PUSCH 자원의 주파수 축 서브캐리어 수를,

는 PUSCH 자원이 할당된 SC-FDMA 심볼 수를, K_r은 r번째 코드 블록에서 전송되는 비트 수를,

는 설계 파라미터를 의미하며,

는 올림(ceiling) 기호를 의미한다. 이후, 각 k번째 CG에 대한 코딩된 심볼 수(또는 코딩된 비트) N_k는 해당 CG의 페이로드 크기가 B_k비트일 때, 상기 수학식과 같이 계산할 수 있다. 이 때, 각 CG별 UCI 자원은 상기 N_tot개 코딩된 심볼들 내에서 서로 중복되는 자원(예컨대, 코딩된 심볼, RE)를 갖지 않는다. here,

Is the number of subcarriers in the frequency axis of the allocated PUSCH resource,

is the number of SC-FDMA symbols to which PUSCH resources are allocated, K _r is the number of bits transmitted in the r-th code block,

is the design parameter,

means a ceiling sign. Then, the number of coded symbols (or coded bits) N _k for each k-th CG can be calculated as in the above equation when the size of the payload of the corresponding CG is B _k bits. In this case, UCI resources for each CG do not have resources (eg, coded symbols, REs) overlapping with each other within the N _tot coded symbols.

-Second method: A method of deriving UCI resources (eg, coded symbols or coded bits for UCI transmission) based on the size of the UCI payload of each CG

(Example) In case of transmitting 1 TB in LTE system

In the case of the second method, based on the UCI payload size B _k for the specific k-th CG, the number N _k of all coded symbols in the PUSCH resource can be derived as shown in the following equation.

For convenience of description of the present invention, the UCI resource for each CG calculated according to the first method (or the UCI resource for each CG that is divided so that different CGs do not have overlapping resources for all UCI resources) is "UCI resource for each CG" The UCI resource for each CG calculated according to the second method as "type 1" is named "UCI resource type 2 for each CG".

Hereinafter, a method of corresponding the UCI resource for each CG to a logical resource composed of sequential REs will be described.

(1) A method of sequentially allocating UCI resource type 1 for each CG in the logical resource domain

Specifically, the present invention proposes a method of transmitting UCI for each CG in UCI resource type 1 for each CG that does not have overlapping REs defined as in 1.1 above. At this time, the UCI for each CG is generated in the form of a mother code to which a coding technique such as RM coding is applied, and if the bits of the mother code are smaller than the bits that can be transmitted in the UCI resource type 1, cyclic repetition is performed, If it is large, it can be transmitted in the UCI resource type 1 after rate matching by truncating the latter part of the mother code. In this case, the entire UCI resource (or logical resource region) may have a structure in which UCI resource type 1 of each CG is sequentially present according to the index or priority of the CG.

For example, assume that logical resource regions are defined as shown in FIGS. 7 and 8, UCI resource type 1 for CG ₁ is 11 REs, and UCI resource type 1 for CG ₂ is 11 REs. In this case, as shown in FIG. 9 , UCI resource type 1 for CG ₁ and UCI resource type 1 for CG ₂ may be sequentially allocated within the logical resource region.

(2) A method of allocating UCI resource type 2 for a specific CG after performing the process of (1)

On the other hand, the UCI resource type 1 for each CG is based on the UCI payload for each CG due to the constraint on the maximum UCI resource that can be allocated for UCI transmission in the PUSCH resource. To ensure a coding rate It may have a value smaller than the calculated UCI resource type 2 for each CG. At this time, if specific CG ₁ is mainly composed of CCs in a licensed band and CG ₂ is composed mainly of CCs in an unlicensed band, priority is given to UCI transmission for CG ₁ , which is relatively sensitive to the timing of the HARQ process. can have As in the case illustrated above, if the UCI resource type 1 for a specific CG with higher priority of UCI transmission is smaller than the UCI resource type 2, some of the UCI resources for the CG with lower priority than the corresponding CG are allocated to the CG with higher priority. It can be designed to be allocated to UCI resource type 2 for . Alternatively, as in (1), all UCI resources are divided into units of UCI resource type 1 for each CG, and then, a CG with a higher priority generates a coded symbol based on UCI resource type 2, so that a CG with a lower priority than itself UCI resource type 1 may be punctured.

For example, suppose that UCI resource type 1 for each CG is sequentially allocated to all UCI resources (or logical resource regions) within the PUSCH resource through the process of (1) above. In this case, in the process of sequentially allocating UCIs, if the priority of the CG to which the nth UCI is allocated (eg, CG ₁ ) is higher than the CG to which the n+1th UCI is allocated (eg, CG ₂ ), CG ₁ For UCI, coding is performed _{in units of UCI resource type 2, and up to UCI resource type 1 units for CG 1 are preferentially} allocated. It can be allocated sequentially starting from the front of the inside. In this case, UCI for CG ₂ may be sequentially allocated within UCI resource type 1 for CG ₂ after the UCI resource allocation for CG ₁ ends. 10 shows the above example.

Alternatively, in the above example, the UCI for CG ₂ is allocated by applying coding based on UCI resource type _{1 for CG 2 as} shown in FIG. The remaining UCI resources remaining after being allocated to UCI resource type ₁ for CG ₂ may be allocated in a manner of puncturing the front of UCI resource type 1 for CG 2. 11 is a schematic diagram of the above example.

(3) A method of sequentially allocating UCI resource type 2 for each CG in the logical resource domain

If the priority between CGs is important, a method of sequentially allocating UCI resources in units of UCI resource type 2 for each CG in the order of priority CGs without considering UCI resource type 1 may be considered. As an example, in the case of HARQ-ACK, assume that logical resource regions are defined as shown in FIGS. 7 and 8, UCI resource type 2 for CG ₁ is 15 REs, and UCI resource type 2 for CG ₂ is 12 REs. Then, as shown in (a) or (b) of FIG. 12, UCI resource type 2 for CG ₁ and UCI resource type 2 for CG ₂ can be sequentially allocated.

Here, (a) of FIG. 12 illustrates a case in which UCI resources for CG ₂ are transmitted even though they are cut, and (b) of FIG. 12 illustrates a case in which transmission of UCI resources for CG ₂ is omitted. .

1.3 Allocation based on starting index and ending index in logical resource area

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource and a logical resource region composed of sequential REs is defined as in the above method, the base station performs a UCI resource allocation for each CG. The starting index and the last index (or the starting index and the number of allocated REs) in the logical resource region are set to the UE, and the UE proposes a method of allocating UCI resources for each CG from the corresponding starting index to the last index. In this case, if the number of REs required for UCI resource allocation is greater than the number of REs allocated by the base station in terms of coding gain for a specific CG, UCI resource transmission for the CG may be omitted.

As an example, in the case of HARQ-ACK, assume that logical resource regions are defined as shown in FIGS. 7 and 8, and that UCI resources for CG ₁ are 15 REs and UCI resources for CG ₂ are 12 REs. In this case, if the base station sets the start index and the end index of UCI resource allocation for CG ₁ and CG ₂ to (0, 10) and (11, 21), respectively, UCI resources for each CG can be allocated as shown in FIG. 13 .

1.4 Allocation based on start index and puncturing operation in logical resource area

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource and a logical resource region composed of sequential REs is defined as described above, the base station provides priority information for the CGs. (or order information) and the starting index in the logical resource region for UCI resource allocation for each CG, the UE allocates UCI resources starting with CGs having a lower priority (or following in order), and assigning a higher priority A method of allocating UCI resources for a CG having (or preceding in order) a UCI resource for a lower CG is punctured.

For _example , in the case of _HARQ - _ACK , a logical resource region is defined as shown in _FIG . let's say Then, UCI resources for each CG can be transmitted as shown in FIG. 14 according to the above scheme.

The above-described allocation based on the start index/last index and allocation based on the start index/puncturing operation may be applied in combination. That is, UCI resources for each CG have a start index, and may be allocated while puncturing existing allocated resources or allocated up to the last index, depending on whether the base station is configured.

As described above, UCI resources may be represented by REs at physical locations in the time/frequency resource domain by a correspondence between the logical resource domain and the time/frequency resource domain. For example, when UCI resources for two CGs are divided in logical resources as shown in FIG. 13, they can be expressed as actual physical resources as shown in FIG. 15 by the correspondence between FIGS. 7 and 8.

Similarly, UCI resources in FIG. 14 may be expressed as actual physical resources as shown in FIG. 16 .

2. Time/Frequency Resource Domain

2.1. A method of allocating UCI resources for each CG to different SC-FDMA symbols

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource, a base station sets a resource region to which UCI resources for each CG can be allocated to the UE as a plurality of SC-FDMA symbols. and a method of setting the SC-FDMA symbol set to which UCI resources are allocated for each different CG is not the same. Alternatively, more generally, the base station may allocate UCI resources for each CG to time resources that are distinguished from each other.

As an example, in the case of HARQ-ACK, as shown in FIG. 7, the maximum region to which coded symbols of HARQ-ACK within PUSCH resources can be allocated is 4 SC-FDMA symbols adjacent to PUSCH demodulation reference signal (DM-RS) (ie, , SC-OFDM symbols of indexes 2, 4, 9, and 11). In addition, assuming that the terminal transmits UCI for two CGs (eg, CG ₁ and CG ₂ ) on PUSCH resources, for example, the maximum resource region to which the UCI resource for CG1 can be allocated is the SC of indexes 2 and 4 -FDMA symbol, and the maximum resource region to which UCI resources for CG ₂ can be allocated can be set to SC-OFDM symbols of indexes 9 and 11.

17 shows an example of a case where UCI resources for CG ₁ are 15 REs and UCI resources for CG ₂ are 12 REs.

2.2 A method of allocating UCI resources for each CG to different RBs

According to a specific embodiment of the present invention, when a UE transmits UCI for a plurality of CGs on a PUSCH resource, a base station configures a plurality of RBs as a resource region to which UCI resources for each CG can be allocated to the UE, and the mutual We propose a method of setting RB sets to which UCI resources for different CGs are allocated so that they are not the same. Or more generally, the base station may allocate UCI resources for each CG to frequency resources that are distinguished from each other.

As an example, in the case of HARQ-ACK, assuming that the UE transmits UCIs for two CGs (eg, CG ₁ and CG ₂ ) with 15 REs and 12 REs, respectively, on a PUSCH resource composed of 2 RBs, as shown in FIG. UCI resources for each CG may be allocated to different RBs.

- How to selectively transmit UCI for each CG

According to a specific embodiment of the present invention, a UE transmits UCI for a plurality of CGs on a PUSCH resource, and as in the UCI resource allocation method for each CG (individual coding is applied for each CG), the UCI resource for each CG is classified in a resource region. When this occurs, the UE selectively transmits UCI for a specific CG, and the base station performs BD (blind detection) for each resource region to which UCI resources for each CG are allocated to detect whether or not UCI is transmitted from a specific CG. At this time, the base station may detect the UCI by giving priority to a CG having a high priority (or prior in order). At this time, from the UE point of view, for a CG that has not received a PDSCH/PDCCH (requiring ACK/NACK feedback), UCI is not transmitted and corresponding UCI resources are filled with data. In other words (for each CG), if there is no scheduling for all cells belonging to the CG, data may not be punctured for the UCI resource corresponding to the corresponding CG. Conversely, scheduling for at least one cell belonging to the CG If there is, data may be punctured for a UCI resource corresponding to the corresponding CG, and UCI (eg, ACK/NACK) corresponding to the corresponding CG may be mapped.

As an example, in FIG. 18, when there is no HARQ-ACK information to be transmitted for CG ₁ because PDSCH scheduling does not exist at the reference time point of HARQ-ACK transmission for CG ₁ , as shown in FIG. 19, UCI for CG ₁ is Data transmission may be performed in the corresponding UCI resource without transmission.

[Example of CG composition]

When naming a cell defined in a licensed band as an L-cell and a cell defined in an unlicensed band as a U-cell, one of the following CG configurations can be considered as an example of a CG configuration in which the proposed method can be utilized. there is.

(1) CG composed only of L-cells (CG ₁ ) and CG composed only of U-cells (CG ₂ )

(2) CG consisting only of L-cells (CG ₁ ) and CG including U-cells and L-cells (CG ₂ )

(3) CG including L-cell and U-cell (CG ₁ ) and CG consisting only of U-cell (CG ₂ )

(4) CG composed only of L-cells (CG ₁ ), CG including L-cells and U-cells (CG ₂ ), and CG composed only of U-cells (CG ₃ )

The U-cell performs opportunistic PDSCH transmission based on a listen before talk (LBT) operation. Therefore, in the examples (1), (2), and (3), CG ₂ includes many U-cells and Compared to ₁ , the PDSCH transmission probability is relatively low.

For example, in the CG configuration example, when only PDSCH transmission exists in CG ₁ and PDSCH transmission does not exist in CG ₂ , HARQ-ACK for CG ₁ applies individual coding to obtain UCI corresponding to CG ₁ . It is transmitted in a resource, and HARQ-ACK for CG ₂ may be omitted.

For example, in the case of HARQ-ACK, in the FDD system of LTE, the terminal may transmit HARQ-ACK for PDSCH transmission at a specific time point to PUSCH through UCI piggyback. If there is no PDSCH transmitted at this point in time, the UE may not allocate coded symbols for HARQ-ACK within the PUSCH resource at all (eg, DTX). At this time, the base station may determine whether the UE reports HARQ-ACK by performing BD assuming that coded symbols for HARQ-ACK are allocated. Therefore, in the existing LTE system, it can be assumed that the base station has BD capability for HARQ-ACK transmission or not.

However, the BD capability of the base station is expected to be able to determine only whether or not UCI is transmitted assuming a pre-promised UCI payload size (or UCI resource) in a pre-promised resource area. For example, assume that a total of 5 CCs are configured for the UE, and PDSCHs are transmitted on 2 of these CCs, so that the UE reports only the HARQ-ACK for the 2 CCs through the PUSCH. In this case, there is a possibility of determining that the base station performs BD and reports HARQ-ACK for two CCs, but it is unknown which CCs the two CCs mean among the five CCs.

Therefore, the present invention defines UCI resources for each CG mutually recognized between the base station and the terminal, and divides and allocates the UCI resources for each CG in a resource region so that the base station can support BD whether or not to transmit UCI for each CG. The above operation is resource efficient by allowing the UE to omit HARQ-ACK transmission for a specific CG in which detection fails or HARQ-ACK of PDSCH for all CCs in the CG is NACK/DTX when the large-scale CA technique is applied. will make it usable.

Hereinafter, a method of extending and applying the DAI concept in a TDD system when a UE transmits UCI for multiple CGs through a PUSCH and UCI for each CG is distinguished will be described.

UCI resource adaptation based on explicit signaling of the base station

The following description considers the following example CG configuration.

[Example of CG composition]

When a cell defined in a licensed band is named an L-cell and a cell defined in an unlicensed band is named a U-cell, the following CG configuration can be considered as an example of a CG configuration in which the proposed scheme can be utilized.

(1) CG composed only of L-cells (CG ₁ ) and CG composed only of U-cells (CG ₂ )

(2) CG consisting only of L-cells (CG ₁ ) and CG including U-cells and L-cells (CG ₂ )

(3) CG including L-cell and U-cell (CG ₁ ) and CG consisting only of U-cell (CG ₂ )

(4) CG composed only of L-cells (CG ₁ ), CG including L-cells and U-cells (CG ₂ ), and CG composed only of U-cells (CG ₃ )

The U-cell performs opportunistic PDSCH transmission based on a listen before talk (LBT) operation. Therefore, in the examples (1), (2), and (3), CG ₂ includes many U-cells and Compared to ₁ , the PDSCH transmission probability is relatively low.

As described above, when the PDSCH transmission opportunities for each CG are different, the frequency of corresponding UCI transmission may also be different. Therefore, the present invention proposes a scheme in which the base station instructs the UE with UCI resources (or UCI payload size) for each CG through explicit signaling in consideration of the case where the frequency of UCI transmission for each CG is different.

- UL signaling

1. UL DAI transmission for each CG

According to a specific embodiment of the present invention, a UE applies a UCI piggyback method including the above-described proposal for UCI for a plurality of CGs to a PUSCH resource, for example, separate coding for each CG or coding for all UCIs without CG distinction. When applied and transmitted, a scheme in which the base station informs the number of DL subframes that the UE should consider in the process of calculating the UCI resource (or UCI payload size) for each CG as a UL DAI value for each CG is proposed. The UL DAI for each CG may be included in control signaling (eg, DCI) indicating transmission of the PUSCH resource.

In the TDD system of LTE, a case may occur in which HARQ-ACK for a plurality of DL subframes must be transmitted in one UL subframe due to an asymmetric structure of DL/UL subframes. At this time, in the LTE system, in order to reflect the number of DL subframes in which PDSCH transmission is actually performed to the HARQ-ACK payload size, DL DAI and UL indicating the cumulative number of DL subframes in which PDSCH is transmitted within a certain DL subframe interval DAI was introduced. For example, when all N PDSCHs are transmitted, the UE can know the PDSCH transmitted n (= 0, 1, 2, ..., N-1) through the DL DAI, and for some PDSCHs Even if detection fails, PDSCHs that are omitted in the middle can be known through DL DAI and the total number can be known through UL DAI, so HARQ-ACK for PDSCHs that have failed detection is treated as DTX and HARQ-ACK for all N PDSCHs will be able to report

If it is a TDD system and the CA technique is considered, the UE can transmit HARQ-ACK for multiple CCs on PUSCH resources, and the number of DL subframes indicated by the UL DAI is equally applied to all CCs. For example, when the number of DL subframes in which the actual PDSCH is transmitted is 3 in CC ₁ and 1 in CC ₂ , the UL DAI value may be transmitted to indicate 3, which is the maximum number of DL subframes for the two CCs. Then, the UE configures HARQ-ACK assuming that 3 DL subframes are transmitted for both CC ₁ and CC ₂ , and at this time, all HARQ-ACK for CC ₂ except for 1 DL subframe are reported as DTX do. As described above, when a uniform UL DAI value is applied to multiple CCs, HARQ-ACK is reported mainly in DTX for CCs with a small number of DL subframes in which actual PDSCH transmission is performed, resulting in inefficient UCI resource allocation.

In the existing LTE Rel-12 system, only the case where the maximum number of CCs supported by the CA scheme is 5 is considered, and thus the inefficiency of applying UL DAI to all CCs collectively has been overlooked. In 13, when a large-scale CA technique is introduced, this problem may be highlighted as up to 32 CCs are considered. That is, the deviation of the number of DL subframes in which PDSCH transmission is performed between 32 CCs may be more severe than the deviation of the number of DL subframes in which PDSCH transmission is performed between 5 CCs. In order to solve the above problem, the present invention proposes a method of independently setting the UL DAI in CG units by informing the UE of the UL DAI in CG units. As an example, in the above example, the base station sets values corresponding to three DL subframes for DAI for CC ₁ and one DL subframe for DAI for CC ₂ , so that HARQ-ACK transmission for CC ₂ is performed by the UE. may be instructed to omit it.

For example, in the above CG configuration example, when PDSCH transmission is performed in 4 DL subframes in CG ₁ and PDSCH transmission in CG ₂ is performed in 1 DL subframe, according to the UL DAI transmission method for each CG The base station may inform the terminal through DCI that the UL DAI for CG ₁ indicates 4 DL subframes, and the UL DAI for CG ₂ indicates 1 DL subframe.

FIG. 20 illustrates, for example, a structure in which UL DAI for each CG is supported for up to two CGs (eg, CG ₁ and CG ₂ ) in DCI format 0.

Here, CIF (Carrier indicator field) is a carrier indicator field, 0/1A is a field for distinguishing DCI format 0/1A, FH + Contiguous RA is a field expressing continuous resource allocation with frequency hopping, and similarly multi- Clustered RA is a field representing multi-cluster-based resource allocation, MCS/RV is a field representing a combination of MCS (modulation and coding scheme) and RV (redundancy version), NDI (new data indicator) is a field indicating whether new data is transmitted, DM-RS CS is a field indicating a cyclic shift of the DM-RS, CQI req. is a field indicating performance of aperiodic CSI reporting, SRS is SRS ( A field indicating whether a sounding reference signal is transmitted, and RAT are fields indicating a resource allocation type (ie, contiguous RA or multi-clustered RA). In the case of transmitting UL DAI for each CG as in the above example, multiple UL DAIs for a plurality of CGs can be transmitted as one method.

As an additional operation of the UL DAI transmission method for each CG, the base station transmits a single bit field to the terminal by dynamic signaling such as DCI, and the UL DAI value applied for UCI piggyback in multiple CGs through the bit field ( Or the number of DL subframes) may be indicated. That is, one state of the bit field may indicate a combination of UL DAI values (or the number of DL subframes) for multiple CGs. For example, assuming a 2-bit bit field, each state can be defined as shown in Table 8 below.

State of a 2-bit field UL DAI combination for multiple CGs 00 UL DAI=1 for CG ₁ , UL DAI=1 for CG ₂ 01 UL DAI=2 for CG ₁ , UL DAI=2 for CG ₂ 10 UL DAI=3 for CG ₁ , UL DAI= ₂ for CG 2 11 UL DAI=4 for all CGs

2. Transmission of UCI piggyback on/off indicators for each CG

According to a specific embodiment of the present invention, a UE applies a UCI piggyback method including the proposal described above to UCI for a plurality of CGs to a PUSCH resource, for example, individual coding for each CG or applying coding to all UCIs without distinguishing CGs. and transmits information on CGs that the terminal should consider in the process of calculating UCI resources (or UCI payload size), the base station transmits an on/off indicator indicating whether UCI piggyback for each CG for a specific UCI is transmitted. Suggest. The UCI piggyback on/off indicator for each CG may be included in control signaling (eg, DCI) indicating transmission of the PUSCH resource.

For example, in the CG configuration example in the UCI resource adaptation method based on explicit signaling of the base station, when PDSCH transmission exists in CG ₁ and PDSCH transmission does not exist in CG ₂ , UCI piggyback on/off indicators are transmitted for each CG. According to the method, the base station instructs the terminal to piggyback the UCI of CG ₁ to the PUSCH resource through the UCI piggyback on/off indicator (ie, “on”), and not to piggyback the UCI for CG ₂ to the PUSCH resource. (i.e. "off").

When the large-scale CA technique is applied in the FDD system, when performing UCI piggyback on PUSCH resources, as in the existing LTE system (eg, Rel-10/11/12), the UCI for all CCs configured by the base station to the terminal is Considering this, UCI signaling overhead may increase excessively. Therefore, in the case of an FDD system, in order for a base station to reduce UCI signaling overhead, a specific CG (e.g., an explicit signaling-based UCI resource adaptation method of the base station) through a UCI piggyback on/off indicator for each CG as in the above proposed method In the configuration example in CG ₂ ), an operation instructing to omit UCI transmission may be useful.

When the large-scale CA technique is applied in the TDD system, when the base station informs the terminal of the UL DAI for each CG as in the UL DAI transmission scheme for each CG, the terminal transmits UCI in response to the maximum number of DL subframes in which PDSCH transmission for each CG is performed. The payload size (or UCI resource) can be set more efficiently. However, the above method may increase the load of DL control signaling by requiring UL DAI for each of a plurality of CGs in DCI indicating PUSCH resource transmission. Therefore, the present invention proposes a method of transmitting an on/off indicator indicating whether UCI piggyback is performed for a specific UCI for each CG as a simpler method. For example, in the case of HARQ-ACK, if the UCI piggyback on/off indicator for CG ₁ in the DCI indicating the PUSCH resource indicates an “off” state, the UE skips UCI transmission for the corresponding CG ₁ and uses the corresponding UCI resource can be filled with data and transmitted.

In this case, the existing UL DAI field for the TDD system may be transmitted together with the UCI piggyback on/off indicator for each CG, and the UL DAI indicates that the UCI piggyback on/off indicator for each CG indicates an “on” state. It can be applied effectively only to CGs. 21 illustrates a structure in which, for example, DCI format 0 supports UCI piggyback on/off indicators for each CG for up to two CGs (eg, CG ₁ and CG ₂ ). Alternatively, in the case of TDD, only the UCI piggyback on/off indicator may be transmitted while UL DAI field configuration and signaling are omitted. Alternatively, it is also possible to set a UL DAI for a specific CG and a UCI piggyback on/off indicator for other CGs.

3. Method of independently setting the number of DL subframes corresponding to UL DAI for each CG

According to a specific embodiment of the present invention, a UE applies a UCI piggyback method including an individual UCI coding/resource mapping method for each CG to PUSCH resources for UCI for a plurality of CGs, for example, individual coding for each CG or CG classification When coding is applied and transmitted to all UCIs without coding, the base station independently configures information on the CG group to which a specific UL DAI is applied and the number of DL subframes corresponding to the UL DAI value for each CG through a higher layer signal to the terminal After receiving the UL DAI from the base station, the UE independently interprets and applies the number of DL subframes to be considered for UCI transmission indicated by the UL DAI value for each CG for the CG group to which the UL DAI is applied. suggest a plan That is, the base station may be set so that the UE interprets the UL DAI differently for each CG, maintaining the interpretation of the UL DAI for a specific CG, and interpreting all or a specific part of the UL DAI value differently for another specific CG.

The method of transmitting the UL DAI value for each CG to the UE according to the UL DAI transmission method for each CG has the advantage of efficiently allocating the UCI resource within the PUSCH resource by informing the number of DL subframes to be considered when transmitting the UCI for each CG. However, the UL DAI transmission scheme for each CG requires a multi-DAI structure as shown in FIG. 20, which also has a disadvantage of increasing control signaling overhead.

Meanwhile, in the large-scale CA scheme, which is the background of the present invention, some CCs may be configured in a licensed band in which PDSCH transmission is stable, and the remaining CCs may be configured in an unlicensed band in which PDSCH transmission occurs opportunistically. At this time, considering the TDD system, CCs configured in the unlicensed band may have a relatively smaller number of DL subframes in which PDSCH transmission occurs than CCs configured in the licensed band.

)를 DL 서브프레임 수 (예,

)에 대응시킬 수 있다.From the above point of view, according to the CG configuration example in the explicit signaling-based UCI resource adaptation method of the base station, PDSCH is transmitted in CG 2 for CG ₁ configured mainly _{for CCs of licensed bands and CG 2 configured} mainly for CCs of unlicensed bands. The range of the number of possible DL subframes may be smaller than the range in CG ₁ , and therefore, it may be desirable to interpret the DL subframes indicated by the UL DAI differently for each corresponding CG. As an example, in the case where the CA technique of the Rel-12 LTE system is applied and the TDD UL/DL configuration {1, 2, 3, 4, 6} and HARQ-ACK is piggybacked to the PUSCH, the terminal receives UL DAI as shown below (yes,

) to the number of DL subframes (eg,

) can be matched.

[Note 1]

=

. The UE shall not transmit HARQ-ACK on PUSCH if the UE does not receive PDSCH or PDCCH/EPDCCH indicating downlink SPS release in subframe(s) n-k where k∈K and

=4.- For TDD UL/DL configurations {1, 2, 3, 4, 6} and a PUSCH transmission adjusted based on a detected PDCCH/EPDCCH with DCI format 0/4, the UE shall assume

=

. The UE shall not transmit HARQ-ACK on PUSCH if the UE does not receive PDSCH or PDCCH/EPDCCH indicating downlink SPS release in subframe(s) nk where k∈K and

=4.

As an example of applying the operation of the present invention (if the number of DL subframes corresponding to ACK/NACK feedback timing in common to one UL subframe is defined as M), the base station sends the UE to the upper layer such as RRC The maximum value of the number of DL subframes in which PDSCH is scheduled for each CG through signaling is set to N _DL,max,c (<M), and the terminal applies the maximum number of DL subframes indicated by the N _DL,max,c Thus, the number of DL subframes in which the PDSCH is scheduled can be calculated as shown in the following equation.

As an application of the above example, the corresponding relationship between the UL DAI and the DL subframe presented in Reference 1 is applied to CG ₁ based on a licensed band CC, and for CG ₂ based on an unlicensed band CC, as in Equation 5, in CG ₂ A correspondence relationship between UL DAI and DL subframes that limits the number of DL subframes in which PDSCH is scheduled to a maximum of N _DL,max,c may be applied.

)를 DL 서브프레임 수(예,

)에 대응시킬 수 있다.In addition, when TDD UL/DL configuration is 5 and HARQ-ACK is piggybacked on PUSCH, the UE transmits UL DAI (e.g.,

) to the number of DL subframes (eg,

) can be matched.

[Note 2]

, where U denotes the maximum value of U_c among all the configured serving cells, U_c is the total number of received PDSCHs and PDCCH/EPDCCH indicating downlink SPS release in subframe(s) n-k on the c-th serving cell, k∈K. The UE shall not transmit HARQ-ACK on PUSCH if the UE does not receive PDSCH or PDCCH/EPDCCH indicating downlink SPS release in subframe(s) n-k where k∈K and

=4.- For TDD UL/DL configurations 5 and a PUSCH transmission adjusted based on a detected PDCCH/EPDCCH with DCI format 0/4, the UE shall assume

, where U denotes the maximum value of U _c among all the configured serving cells, U _c is the total number of received PDSCHs and PDCCH/EPDCCH indicating downlink SPS release in subframe(s) nk on the c-th serving cell, k∈ K. The UE shall not transmit HARQ-ACK on PUSCH if the UE does not receive PDSCH or PDCCH/EPDCCH indicating downlink SPS release in subframe(s) nk where k∈K and

=4.

In Reference 2, one UL DAI value may mean a plurality of DL subframes in association with the number of detected PDSCHs (eg, U), which means that the probability of failing to detect 4 or more PDSCHs consecutively is very low. Because. However, in the unlicensed band CC, the probability of PDSCH detection failure may be higher, and therefore, the DL subframe group that the UE can reliably identify may be different from the value suggested in Reference 1 above. For example, assuming that the probability of continuously failing to detect 5 PDSCHs in the unlicensed band CC is low, a correspondence relationship between UL DAI and DL subframes can be set as shown in the following equation.

Additionally, the base station sets a reference for the number of DL subframes corresponding to the UL DAI value in advance, and adds a bit field to the DCI indicating the PUSCH resource to determine whether a specific UL DAI complies with the reference setting. Alternatively, it may indicate whether independent settings for each CG according to the operation of the present invention are followed. For example, by adding 1 bit to the DCI, whether the UL DAI applies the number of DL subframes according to the correspondence relationship of Reference 1 to all CGs or the number of DL subframes according to the correspondence relationship of Table 8 for each CG It can tell you whether it is applied independently or not.

The operation of the present invention may be extended and applied to DL DAI. That is, the base station may independently set the number of DL subframes or interpretation indicated by the DL DAI for each CG to the terminal.

According to a specific embodiment of the present invention, a UE applies a UCI piggyback method including an individual UCI coding/resource mapping method for each CG to PUSCH resources for UCI for a plurality of CGs, for example, individual coding for each CG or CG classification When coding is applied to all UCI without coding, the base station sets an offset value for the UL DAI value (or the number of DL subframes indicated by the UL DAI value) for each CG through a higher layer signal to the terminal, and for each CG A method of notifying an indicator indicating whether to apply a UL DAI offset value in the UCI piggyback process of the PUSCH resource through dynamic signaling is proposed.

As a modified operation of the method of independently setting the number of DL subframes corresponding to the UL DAI for each CG, the UL DAI offset value for each CG is set in advance to distinguish the interpretation of the UL DAI value for each CG, and the base station again A method of more flexibly adjusting the UCI payload size by transmitting dynamic signaling indicating whether the UL DAI offset is applied may also be considered.

- DL signaling

1. DL/UL DAI (hereinafter referred to as “DL/UL DAI across CCs per CG”) transmission considering all CCs per CG (across CCs)

According to a specific embodiment of the present invention, a UE applies a UCI piggyback method including an individual UCI coding/resource mapping method for each CG to PUSCH resources for UCI for a plurality of CGs, for example, individual coding for each CG or CG classification When all UCIs are coded and transmitted without coding, DL control signaling (e.g., DCI) indicating transmission of a specific PDSCH transmitted within the CG means the cumulative number of transmissions of all PDSCHs within the CG up to the time of transmission of the corresponding PDSCH. We propose a method of notifying the UE including the DL DAI. The DL DAI means a value obtained by accumulating all the numbers of PDSCHs transmitted during all CCs in the CG and all DL subframe intervals configured in the TDD system. Similarly, the base station includes a UL DAI indicating the cumulative number of PDSCHs (assuming all CCs and all configured DL subframe intervals) that the terminal will commonly assume for all CGs in the DCI indicating transmission of the PUSCH to inform the terminal. can In this case, the order between PDSCH transmissions indicated by the DL DAI in the CG may be given in a time-first manner. Here, the number of all PDSCHs transmitted during all CCs in the CG and all DL subframes configured in the TDD system can be calculated by summing the number of DL subframes in which PDSCHs are transmitted for each CC. The operation according to this method extends the concept of the existing DAI, and has the advantage of reusing the existing signaling.

However, in the LTE system according to the embodiment of the present invention, there is no separate UL / DL DAI field in DCI in case of FDD system, and in case of UL-DL configuration #0 in TDD system, the DAI field of DCI format 0 is UL DAI It is used for indicating a UL index for multi-UL subframe scheduling, not for its intended purpose. Therefore, preferably, the DL/UL DAI for counting PDSCH transmissions for the DL subframe period and CCs configured in the CG may be provided in one of the following two methods.

(i) Introducing an additional bit field in DCI

(ii) (In case of TDD UL-DL configuration #0) UL DAI value is set in advance for each UL index state

In this case, when a bit field is added to the DCI according to the method (i), the DCI including the added bit field must be defined only when transmitted in a UE-specific search space (USS). This is because it is not desirable to introduce an additional bit field to DCI format 0 in CSS when considering coexistence with a terminal performing a legacy operation and fallback operation in a common search space (CSS).

The DL/UL DAI across CCs for each CG may be signaled only for a specific CG and not signaled for other CGs. For example, the DL/UL DAI across CCs may not be signaled for CGs composed only of L-cells, and the DL/UL DAI across CCs may be signaled for CGs including U-cells.

2. DL DAI signaling and UE interpretation method in multi-CC/multi-subframe scheduling

2.1. Individual DL DAI setting and interpretation according to single/multiple PDSCH scheduling

According to a specific embodiment of the present invention, the base station informs the terminal of the DCI indicating transmission of a specific PDSCH, including the DL DAI indicating the number of PDSCH transmissions accumulated until the transmission of the corresponding PDSCH, and DCIs indicating single PDSCH scheduling are DCI type When (type) 1 and DCIs indicating multiple PDSCH scheduling are referred to as DCI type 2, a method of setting the UE to interpret the value indicated by the DL DAI independently within each DCI type is proposed. That is, DL DAI in DCI type 1 means the cumulative transmission number of PDSCHs indicated by DCI type 1, and DL DAI in DCI type 2 means the cumulative transmission number (or DL scheduling number) of PDSCHs indicated by DCI type 2. At this time, the terminal can distinguish the DCI type by the length of the DCI or a radio network temporary identifier (RNTI) value scrambled to CRC bits of the DCI.

In the LTE Rel-8 system according to an embodiment of the present invention, as shown in Reference 3 below, a plurality of cases for the number of subframes in which PDSCH is transmitted in a DL DAI having a 2-bit bit field are expressed. For example, the '00' state of the DL DAI may indicate that 1, 5, or 9 PDSCHs have been accumulated and transmitted. The reason why the number of accumulated transmissions of a plurality of PDSCHs is indicated in one state as described above is that the probability that the UE cannot detect a plurality of consecutive (eg, four) PDCCH (or DCI) transmissions is expected to be very low.

[Note 3]

DAI MSB, LSB VUL,DAI or VDL,DAI Number of subframes including PDCCH/EPDCCH indicating PDSCH transmission and DL SPS release 0,0 One 1, 5 or 9 0,1 2 2, 6 or 10 1,0 3 3 or 7 1,1 4 0, 4 or 8

First, according to the DL/UL DAI acrocc CCs for each CG of the present invention, DL/UL DAI indicates the number of cumulative PDSCH transmissions in the CC domain, and DCI A in a specific DL subframe is 4 CCs (eg, CC ₁ , CC ₂ , Assume that multi-CC scheduling for CC ₃ and CC ₄ is indicated, and DCI B indicates single CC scheduling for one CC (eg, CC ₅ ). In this case, the base station in the DL subframe For a UL subframe in which ACK/NACK resources are transmitted, PUSCH resources may be allocated as DCI indicating UL grant, and ACK/NACK transmission for 5 PDSCHs may be indicated with a UL DAI value in the DCI. Also, assume that the base station first sets the DL DAI value in DCI A to '11' to notify transmission of the accumulated 4 PDSCHs, and sets the DL DAI value in DCI B to '00' to notify transmission of the accumulated 5 PDSCHs.

At this time, if the UE fails to detect DCI A and succeeds in detecting DCI B, if the DL DAI value '00' in DCI B means 1, 5, or 9 cumulative PDSCH transmissions similar to the existing design, the UE It is difficult to determine whether detection of the 1st PDSCH or the 5th PDSCH is successful among 5 PDSCHs. The reason why it is difficult for the UE to determine is that in case of single PDSCH scheduling, to determine '00' as accumulated 5 PDSCHs, it must fail to detect 4 DCIs in a row and the probability of this case occurring is very low. However, when multiple PDSCH scheduling such as multi-CC scheduling is considered, a situation in which it is difficult to make a decision may occur even if the UE fails to detect one DCI as in the above example.

Therefore, in the present invention, the case where the UE indicates single PDSCH scheduling (or DCI indicating single PDSCH scheduling) and the case indicating multiple PDSCH scheduling (or DCI indicating multiple PDSCH scheduling) are interpreted separately. suggest a plan For example, the number of accumulated PDSCH transmissions indicated by the DL DAI in the DCI indicating single PDSCH scheduling does not include PDSCHs corresponding to the DCI indicating multi-PDSCH scheduling. Similarly, the cumulative number of PDSCH transmissions (or the number of DL schedulings) indicated by the DL DAI in the DCI indicating multi-PDSCH scheduling does not include PDSCHs corresponding to the DCI indicating single PDSCH scheduling.

2.2. DL/UL DAI application method for multiple PDSCH scheduling

According to a specific embodiment of the present invention, the base station semi-statically sets the number of PDSCHs or the maximum number of PDSCHs that can be DL-scheduled with one DCI and informs the terminal, and the base station transmits a DCI corresponding to a DCI instructing transmission of a specific PDSCH We propose a method of notifying the terminal including the DL DAI, which means the cumulative number of DL schedulings (or the cumulative number of DCI) up to the point in time. In this case, the cumulative number may be counted during a specific CC group and a specific DL subframe interval prearranged between the base station and the terminal. Similarly, the base station includes a UL DAI indicating the cumulative number of DL scheduling (or cumulative number of DCI or cumulative number of PDSCH) that the UE will assume for HARQ-ACK resource feedback in the DCI indicating transmission of the PUSCH, and informs the UE. there is. In this case, the cumulative number may be counted during a specific CC group and a specific DL subframe period previously agreed between the base station and the terminal. Meanwhile, the UE can calculate the entire HARQ-ACK payload through the number of DL schedulings known from the value of UL DAI and the maximum number of PDSCHs that can be transmitted in each DL scheduling. For example, the total HARQ-ACK payload size may be proportional to the product of the accumulated number of DL schedulings indicated by the UL DAI and the maximum number of PDSCHs that can be indicated by the DL scheduling. In this case, DL scheduling means an operation in which the base station instructs PDSCH transmission through downlink control signaling (eg, DCI, etc.).

Even in the case of multi-PDSCH scheduling, if the DL subframe position in which the corresponding DCI is transmitted is set in advance and the number of PDSCHs supported by the multi-PDSCH scheduling is semi-statically set, DL DAI and UL DAI can be effectively applied can As an example, assume that the UE feeds back HARQ-ACK for the PDSCHs scheduled by the corresponding DCI to the base station in a specific single UL subframe for a DL subframe in which a DCI for multiple PDSCH scheduling is transmitted. Also, assume that the base station sets the number of PDSCHs scheduled for multiple PDSCHs to M.

Then, the base station includes a DL DAI indicating the number of DL schedulings (for multiple PDSCHs) (or the number of DCIs indicating multiple PDSCH transmissions) accumulated until the corresponding DCI transmission to the DCI indicating transmission of the plurality of PDSCHs, and informs the terminal , In addition, the base station includes UL DAI, which means the cumulative number of DL scheduling (for multiple PDSCHs) or the cumulative number of PDSCHs or the cumulative number of DCIs indicating multiple PDSCHs to be assumed by the UE in the DCI indicating transmission of the PUSCH, to the UE. can tell you Then, the UE can calculate the total HARQ-ACK payload size through the accumulated number of DCIs indicated by the UL DAI and the number of PDSCHs of multi-PDSCH scheduling (e.g., M), and checks how many DL schedulings are missed through the DL DAI, If missing DL scheduling is found, NACK may be reported for the corresponding M PDSCHs.

That is, in the manner in which the existing DL DAI and UL DAI operate, only the size of the ACK/NACK payload for each DL scheduling may be increased.

2.3. Individual coding and individual UCI resource allocation schemes according to single/multiple PDSCH scheduling

According to a specific embodiment of the present invention, when a UE piggybacks and transmits UCI on a PUSCH resource, channel coding is applied by distinguishing HARQ-ACK information for single PDSCH scheduling from HARQ-ACK information for multiple PDSCH scheduling, and the classification We propose a method of allocating two groups of coded symbols (that is, coded symbols for single PDSCH scheduling and coded symbols for multiple PDSCH scheduling) to distinct UCI resources.

First, if the HARQ-ACK for multiple PDSCH scheduling is excluded from the HARQ-ACK transmission process for single PDSCH scheduling, the HARQ-ACK transmission process for single PDSCH scheduling additionally determines whether single/multiple PDSCH is scheduled in the existing LTE system. There are advantages to applying the method.

In this case, if the form of multi-PDSCH scheduling is multi-CC scheduling, DCI for single-CC scheduling and DCI for multi-CC scheduling may coexist in a specific DL subframe. In addition, if HARQ-ACK for the PDSCH transmitted in the DL subframe is transmitted through a UCI piggyback procedure within a PUSCH resource in a specific single UL subframe, UL DAI If the interpretation of is multi-CC scheduling, it can be interpreted as the number of DL schedulings, unlike in the past. Therefore, it may be desirable to transmit HARQ-ACK for multi-CC scheduling separately from HARQ-ACK for single CC scheduling. .

In this case, the UL DAI for single PDSCH scheduling and the UL DAI for multiple PDSCH scheduling may each have a distinct bit field.

- UCI adaptation plan in case of UCI on PUSCH over CG

“UCI on PUSCH over CG” refers to an operation in which a UE piggybacks UCIs for CCs belonging to different CGs to a single PUSCH resource.

- Individual/joint UCI coding based on PUCCH standard CG

According to a specific embodiment of the present invention, when a UE can piggyback UCI for CCs belonging to different CGs to a single PUSCH resource (ie, when performing a UCI on PUSCH over CG operation), the PUCCH as follows Individual UCI coding and individual RE mapping (for coded UCI symbols) are applied in units of groups of CCs with the same transmission target cell (hereinafter referred to as PUCCH CG (cell group)), or joint coding and We propose a method of applying corresponding RE mapping.

(1) Applying individual UCI coding and individual RE mapping (for coded UCI symbols) to each of multiple CGs: Here, the plurality of CGs are randomly configured multiple CGs in a single PUCCH situation, or each PUCCH in a dual PUCCH situation. It can be an association or established CG.

(2) Application of joint UCI coding and corresponding RE mapping to all multiple CGs: Here, the multiple CGs may be CGs associated/configured with each PUCCH in a dual PUCCH situation.

In the earlier part of this specification, if individual UCI coding and individual RE mapping schemes for each CG that can be arbitrarily set were proposed, the "PUCCH reference CG-based individual/joint UCI coding" operation performs individual UCI coding and individual RE mapping in PUCCH CG units. Suggest. At this time, when performing UCI piggybacking in PUSCH resources, the UE piggybacks the UCI for the CG within the corresponding CG for which scheduling exists for each PUCCH CG, and piggybacks the UCI for the CG within the corresponding CG for which scheduling does not exist. may not "Individual/joint UCI coding based on PUCCH reference CG" proposes a method of maximizing coding gain by applying joint UCI coding to a plurality of PUCCH CGs when joint UCI coding is applied.

In this case, when individual coding for each PUCCH CG is applied in (1) above, the RE mapping order for coded UCI symbols may follow the index order of the PUCCH CG. Alternatively, in the case of dual PUCCH, a PUCCH CG (hereinafter referred to as PCG) including a primary cell performs RE mapping first, and a PUCCH CG (hereinafter referred to as SCG) not including a primary cell performs RE mapping later. can do. Here, the primary cell refers to a cell in charge of a radio resource control (RRC) connection in a carrier aggregation (CA) environment.

In addition, when joint coding is applied to all PUCCH CGs in (2) above, the input order of the channel coder (eg, Reed-Muller coder) is determined according to the cell index (or CC index) as in the CA environment, or Alternatively, the UCI for PCG may be input first, and the UCI for SCG may be input later. In this case, the order of UCI input as input within each PUCCH CG may follow the cell index (or CC index).

- A/N spatial bundling

According to a specific embodiment of the present invention, when a UE piggybacks UCI for a plurality of PUCCH CGs (that is, a group of CCs with the same PUCCH transmission target cell) on a single PUSCH resource, CCs in all PUCCH CGs When the HARQ-ACK payload size for is larger than a specific B bit (eg, 20 bits), the duplexing scheme of the PUCCH cell for each PUCCH CG and the PUCCH transmission type (eg, PUCCH format 3 (hereinafter, PF3), We propose a method of determining whether to apply spatial bundling (hereinafter, A/N spatial bundling) for HARQ-ACK corresponding to each CG according to a combination of channel selection (hereinafter, CHsel). Here, A/N spatial bundling means that when two or more TBs (transport blocks) are transmitted, an AND operation is applied after obtaining HARQ-ACK bits (eg, bits indicating ACK or NACK) for each TB. . For example, in the case of {ACK (='1'), NACK (= '0')}, NACK (='1' & '0'='0') is derived as a result of spatial bundling.

(1) Option 1: Apply spatial bundling to A/N of all CGs collectively

(2) Option 2: A/N space bundling for each CG is determined according to a combination of a duplexing method and a PUCCH format of a PUCCH cell.

[Example] If up to 5 cells (or CCs) are included in each PUCCH CG, 2 PUCCH cells exist, and B = 20 bits,

PUCCH Cell 1 PUCCH cell 2 PUCCH CG with PUCCH cell 1 PUCCH CG with PUCCH cell 2 TDD-PF3 FDD-PF3 A/N space bundling - TDD-PF3 FDD-PF3 A/N space bundling A/N space bundling TDD-PF3 FDD CHsel A/N space bundling - TDD CHsel FDD-PF3 - - TDD CHsel FDD CHsel - -

At this time, whether or not the B bits are exceeded is determined based on the HARQ-ACK payload size for all PUCCH CGs when joint coding for all PUCCH CGs is applied, and when individual coding for each PUCCH CG is applied, within each CG. The decision is made based on the size of the HARQ-ACK payload. Alternatively, a method for determining whether to perform A/N space bundling for each CG can be defined as follows.

(1) If the HARQ-ACK payload size for all PUCCH CGs exceeds B bits, A/N space bundling is performed for each PUCCH CG until the HARQ-ACK payload size becomes B bits or less according to the priority order below. carry out

A. PUCCH CG (including TDD PF3 PUCCH cell) > PUCCH CG (including TDD CHsel) > PUCCH CG (including FDD PF3 PUCCH cell) > PUCCH CG (including FDD CHsel)

B. If two PUCCH CGs have the same PUCCH cell duplexing scheme and PUCCH transmission type, A/N spatial bundling may be performed first in the SCG or A/N spatial bundling may be performed according to the CG index.

Similarly, in the above case, whether the B bits are exceeded is determined based on the HARQ-ACK payload size for all PUCCH CGs when joint coding is applied to all PUCCH CGs, and when individual coding for each PUCCH CG is applied. It is determined based on the HARQ-ACK payload size in each CG.

As an additional operation of the present invention, if there are a plurality of available PUSCH resources, the terminal transmits only UCI corresponding to one CG to each piggyback target PUSCH, and if there is only one available PUSCH resource, all of the plurality of CGs The UCI corresponding to may be piggybacked and transmitted on the corresponding PUSCH. In this case, in the latter case, individual coding and individual RE mapping may be applied to each of the plurality of CGs. Meanwhile, the former case may be applied only to HARQ-ACK feedback (in the case of CSI feedback, piggyback with one specific PUSCH resource) or applied only to HARQ-ACK feedback and RI/PTI feedback (the rest of the CSI feedback (e.g., CQI/PTI) In the case of PMI), piggyback with one specific PUSCH resource). 22 illustrates an operation of dividing UCI into subsets and transmitting them when the number of available PUSCH resources is plural as an example of the above operation.

As an additional operation of the present invention, there is a CC domain DAI that informs order information (or counting information) of scheduled CCs, and the CC domain DAI consists of only CCs configured to allow transmission of up to 1 TB, CG ₁ and up to 2 When CG ₂ composed of only CCs configured to allow TB transmission is defined for each CG (ie, C-DAI ₁ and C-DAI ₂ ) and included in the DCI for the PDSCH transmitted within the CG and transmitted (in other words, When CC domain DAI is independently applied/signaled for each CG), the following proposal is applicable.

[Proposed Method A-1] Define a total DAI (hereinafter referred to as T-DAI) that informs the total number of CCs scheduled for all CCs included in CG ₁ and CG ₂ apart from the CC domain DAI. and transmits the corresponding T-DAI and the CC domain DAI together through a DL scheduling grant DCI.

For example, it is assumed that CG ₁ is composed of CC ₁ , CC ₂ , CC ₃ , CC ₄ , and CC ₅ , and CG ₂ is composed of CC ₆ , CC ₇ , CC ₈ , CC ₉ , and CC ₁₀ . When the base station schedules CC ₁ , CC ₃ , CC ₄ , CC ₇ , CC ₈ , and CC ₉ , the values of C-DAI ₁ for CC ₁ , CC ₃ , and CC ₄ indicate 1, 2, and 3, respectively, and CC7 , CC8, and the value of C-DAI2 for CC9 may indicate 1, 2, and 3, respectively. At this time, if the terminal does not detect the DCI for all PDSCHs transmitted in the CG ₁ , the base station expects a UCI (eg, A/N) payload of 3 × 1 + 2 × 3 = 9 bits, whereas the terminal By constructing a 6-bit UCI (eg, A/N) payload with 2×3 = 6 bits, mismatch between the base station and the terminal occurs. Therefore, in the present invention, in order to eliminate the mismatch, T-DAI indicating the total number of scheduled CCs as an indicator for the entire UCI (eg, A/N) payload corresponds to all PDSCHs transmitted in CG ₁ or CG ₂ It is proposed to include in the DCI to be included. For example, in the above example, the T-DAI value is indicated by 6, and the base station and the terminal have the value indicated by the T-DAI (eg, 6) and the maximum number of TBs (eg, 2) set to be transmitted from any CC A value corresponding to the product (eg, 6×2 = 12) may be promised as a UCI (eg, A/N) payload.

[Proposed method A-2] The base station sets a specific PUCCH format (or the maximum UCI payload previously set by the base station) with a maximum payload size of N ₁ bits to the terminal in advance, and the terminal in the proposed method A-1 Calculate N ₂ , which is the product of the total number of CCs indicated by the received T-DAI and the maximum number of TBs (eg, 2) set to be transmitted from any CC, and UCI payload size (eg, A / N payload size) Set N to N = min(N ₁ , N ₂ ) bits.

Utilizing the T-DAI defined in the embankment method A-1 of the present invention, the base station and the terminal can promise a UCI (eg, A/N) payload to each other by utilizing the T-DAI. For example, as mentioned above, the base station and the terminal can promise a value corresponding to the product of the value indicated by the T-DAI and the maximum number of TBs (eg, N ₂ ) as a UCI (eg, A / N) payload there is. However, if the base station pre-allocates a PUCCH format in which the maximum UCI (A/N) payload size is N ₁ bits, the UE transmits UCI (eg, A/N) to N ₂ bits when N ₂ is smaller than N ₁ . ), but when N ₂ is greater than N ₁ , it may be preferable to configure the UCI (A/N) payload with N ₁ bits. That is, the UCI payload can be set with min(N ₁ , N ₂ ) bits.

[Proposed method A-3] For the N bits set in the proposed method A-2 (or when N ₁ = N bits without separate T-DAI signaling), the UE uses CG ₁ (CCs with 1 TB) UCI (e.g., A/N) for the configured CG) according to the index order of C-DAI ₁ from LSB (or MSB) on the UCI payload (i.e., C-DAI ₁ with high (or low) UCI bit index low index), and also fill the UCI (eg, A / N) for CG ₂ (CG composed of CCs with 2 TBs) from MSB (or LSB) to C-DAI ₂ in index order (ie , so that the low (or high) UCI bit index is mapped to the low C-DAI ₂ index).

Even if the UCI payload is configured according to the proposed schemes A-2 and A-3, if the DCI for the last CC scheduled for each CG is missing, the UE can access each CC in any order within the UCI payload. It is not known whether the UCI (eg A/N) for For example, in the example of the proposed method A-1, in a state where the UE fails DCI detection for CC ₄ and CC _9, the UCI (eg, A/N) for the scheduled CCs in CG ₁ is C-DAI ₁ Assume that the indices of C-DAI 2 are filled in the order of low indexes, and then the UCIs (eg, A/N) for scheduled CCs in CG ₂ are filled in the order of low indices of C-DAI ₂ . At this time, the base station expects three UCIs (eg, A/N) for 1 TB and three UCIs (eg, A/N) for 2 TB in order, but the terminal expects that the UCI (eg, A/N) for 1 TB comes in order. , A / N) and two UCIs (eg, A / N) for 2 TB are transmitted, resulting in mismatch between the base station and the terminal. Therefore, in the present invention, if the UCI (eg A / N) payload N bits are set in the proposed method A-2, the UCI (eg A / N) for CG ₁ (CG composed of CCs having 1 TB) ) from the LSB (or MSB) in the index order of C-DAI ₁ , and the UCI (eg, A / N) for CG ₂ (CG composed of CCs with 2 TB) from the MSB (or LSB) We propose a method of reducing mismatch between the base station and the terminal by filling in the index order of C-DAI ₂ .

As a specific example, assuming that the bit sequence in which each bit in the UCI payload is listed from the MSB is b ₀ , b ₁ , ... , b _N-1 , C-DAI ₁ = 1, 2, 3 in the above 1-bit UCIs corresponding to bits b _N-1 , b _N-2 , b _N-3 sequentially, and 2-bit UCIs corresponding to C-DAI ₂ = 1, 2, 3 are sequentially bit (b ₀ , b ₁ ), (b ₂ , b ₃ ), (b ₄ , b ₅ ).

As an additional operation of the present invention, there is a CC domain DAI that informs order information (or counting information) of scheduled CCs, and CC domain DAIs are defined for each CG for CG ₁ and CG ₂ (that is, C-DAI ₁ , When the C-DAI ₂ ) is included in the DCI for the PDSCH transmitted in the corresponding CG and transmitted (ie, when the CC domain DAI is independently applied/signaled for each CG), the following operations are proposed.

[Proposed method B-1] When a counter DAI for each CG that informs the number of CCs scheduled for each CG is applied and signaled to multiple CGs, the total DAI that indicates the total number of scheduled TBs within the multiple CGs is applied and signaled propose a way to

For example, CG ₁ composed of only CCs set to allow transmission of up to 1 TB and CG ₂ composed of only CCs set to allow transmission of up to 2 TB are defined for each CG (i.e., C-DAI ₁ and C-DAI ₂ ) and is included in the DCI for the PDSCH transmitted in the corresponding CG and transmitted, CG ₁ is composed of CC ₁ , CC ₂ , CC ₃ , CC ₄ , and CC ₅ , and CG ₂ is composed of CC ₆ , CC ₇ , and CC ₈ , CC ₉ , and CC ₁₀ are assumed. When the base station schedules CC ₁ , CC ₃ , CC ₄ , CC ₇ , CC ₈ , and CC ₉ , the values of C-DAI ₁ for CC ₁ , CC ₃ , and CC ₄ indicate 1, 2, and 3, respectively, and CC The values of C-DAI2 for ₇ , CC ₈ , and CC ₉ may indicate 1, 2, and 3, respectively. Next, assume that the UE has not received only DCI for CC ₉ among scheduled CCs. When applying and signaling T-DAI indicating the total number of scheduled CCs as in A-1 of the present invention, T-DAI informs the terminal that 6 cells are scheduled, and at this time, the terminal is 1 cell It is recognizable that the DCI for is missed, but it is unknown whether the 4th scheduled CC in CG ₁ was missed or whether the 3rd scheduled CC in CG ₂ (ie, CC ₉ ) was missed. A situation arises in which the load calculation is unclear. Therefore, the present invention proposes a method of applying and signaling T-DAI indicating the total number of scheduled TBs in a plurality of CGs. In the above example, if the T-DAI reports the total number of TBs as 1×3 + 2×3 = 9, the UE may determine that scheduling for 2 TBs has been missed. As a specific example, assuming that the missing probability of 4 consecutive cells is small, a 2-bit counter DAI at the cell level is applied to each of the 1-TB CG and the 2-TB CG, and the TB level A full 3-bit DAI of can be applied.

[Proposed method B-2] For two CGs (ie, CG ₁ and CG ₂ ), a counter DAI (ie, C-DAI ₁ and C-DAI ₂ ) per CG that informs the number of CCs scheduled for each CG is applied and When signaled, a total DAI 1 (hereinafter referred to as T-DAI ₁ ) indicating the total number of CCs (or TBs) scheduled among CCs in CG ₁ is defined to provide DL scheduling grant DCI for CG ₁ and transmits it, and defines the entire DAI 2 (hereinafter referred to as T-DAI ₂ ) indicating the total number of scheduled CCs (or the number of TBs) among the CCs in CG ₂ , and includes it in the DL scheduling approval DCI for CG ₂ When transmitting, if the UE determines that there is scheduling for CG ₁ or CG ₂ only, PUCCH resource 1, and if it is determined that scheduling for both CG ₁ and CG ₂ exists, a method of feeding back UCI using PUCCH resource 2 is proposed. .

As described above, when the number of CCs scheduled in each CG is reported as the total DAI for each CG, when all DCIs for a specific CG are missed, a problem of assuming different payloads between the base station and the terminal may occur. Therefore, the present invention proposes a scheme in which a base station can determine a DCI missing problem in a specific CG through blind detection by performing UCI feedback by selecting a PUCCH resource according to a combination of scheduled CGs determined by the UE. More specifically, when there are two CG ₁ and CG ₂ , the base station configures different PUCCH resources for the next three scheduled CG combinations {CG ₁ }, {CG ₂ }, and {CG ₁ , CG ₂ } ( For example, PUCCH ₁ , PUCCH ₂ , PUCCH ₃ ), and the UE may feed back the UCI through the PUCCH corresponding to the scheduled CG combination according to the DCI detection result.

[Proposed method B-3] For two CGs (ie, CG ₁ and CG ₂ ), counter DAI (ie, C-DAI ₁ and C-DAI ₂ ) for each CG that informs the number of CCs scheduled for each CG is applied and When signaled, total DAI ALL (hereinafter referred to as T-DAI) indicating the total number of scheduled CCs (or the number of TBs) among the CCs in CG ₁ and CG ₂ (that is, CCs in the union of CG ₁ and CG ₂ ) _ALL ) is defined and transmitted as included in the DL scheduling grant DCI for CG ₁ , and total DAI 2 (hereinafter referred to as T-DAI ₂ ) indicating the total number of scheduled CCs (or number of TBs) among CCs in CG ₂ is defined and transmitted by including it in the DL scheduling grant DCI for CG ₂ .

Assuming that CG ₁ and CG ₂ are defined as two CGs and that the number of scheduled CCs in each CG is reported as the total DAI for each CG (eg, T-DAI ₁ and T-DAI ₂ ), the base station is part of CG ₁ When scheduling is performed for CCs and some CCs in CG ₂ , the UE can largely recognize the scheduling situation in the following three ways.

(1) It is determined that there is only scheduling for CG ₁ and the A/N payload is calculated as T-DAI ₁ .

(2) It is determined that there is only scheduling for CG ₂ and the A/N payload is calculated as T-DAI ₂ .

(3) It is determined that scheduling for CG ₁ and CG ₂ exists, and the A/N payload is calculated as T-DAI ₁ and T-DAI ₂ .

At this time, the base station must perform blind detection for the above three situations to determine under what assumption the terminal configured the A/N payload (or UCI payload). However, at this time, if the A/N payloads (or UCI payloads) for CG ₁ and CG ₂ have the same value, the base station can determine which CG the A/N (or UCI) was transmitted by the terminal. can't Therefore, in the present invention, for one CG (eg, CG ₁ ) among two CGs (eg, CG ₁ and CG ₂ ), T-DAI _ALL , which informs the number of all CCs (or the number of TBs) scheduled within the two CGs , and for other CGs (eg, CG ₂ ), a method of applying and signaling T-DAI ₂ indicating the number of all scheduled CCs (or the number of TBs) within the corresponding CG is proposed. In this case, the mapping order of the A/N payload (or UCI payload) may follow the order of CG ₁ > CG ₂ . That is, the A/N (or UCI) for the CG to which T-DAI _ALL is applied is first allocated. When operating according to the present invention, in the above example, the terminal can recognize the scheduling situation again in the following two ways.

(1) It is determined that at least CG ₁ is scheduled, and the A/N payload is calculated as T-DAI _ALL .

(2) It is determined that there is only scheduling for CG ₂ and the A/N payload is calculated as T-DAI ₂ .

At this time, since T-DAI _ALL will always have a larger value than T-DAI ₂ , the base station can distinguish it based on the size of the UCI payload.

[Proposed method B-4] For two CGs (ie, CG ₁ and CG ₂ ), a counter DAI (ie, C-DAI ₁ and C-DAI ₂ ) for each CG that informs the number of CCs scheduled for each CG is applied and When signaled, define total DAI 1 (hereinafter referred to as T-DAI ₁ ) indicating the total number of scheduled CCs (or number of TBs) among CCs in CG ₁ , and include it in the DL scheduling grant DCI for CG ₁ and transmit and defines the entire DAI ₂ (hereinafter referred to as T-DAI ₂ ) indicating the total number of scheduled CCs (or the number of TBs) among the CCs in CG 2 and includes it in the DL scheduling approval DCI for CG ₂ and transmits it, We propose a scheme in which the UE adds M bits when providing UCI (or A/N) feedback to indicate which CG combination the feedback was performed on.

For example, in the process of configuring the A/N payload, the terminal adds 2 bits to indicate that there is only A/N for CG ₁ in case of '01', and in case of '10', only A/N for CG ₂ In the case of '11', it can be informed that there is A/N for CG ₁ and CG ₂ . Then, the base station can determine what assumptions the terminal has made regarding the three scheduling situations presented in the example of the proposed method B-3. Alternatively, only whether or not A/N for a specific CG (eg, CG ₂ ) is included can be informed with 1 bit. In this case, a case in which only A/N for CG ₂ is fed back and a case in which A/N for CG ₁ and CG ₂ are fed back can be distinguished by the BD for the A/N payload size.

When the proposed schemes B-1, B-2, B-3, and B-4 are applied, the mapping order on the A/N payload may follow the proposed scheme A-3.

23 is a block diagram showing components of a transmitter 10 and a receiver 20 performing embodiments of the present invention. The transmitting device 10 and the receiving device 20 include radio frequency (RF) units 13 and 23 capable of transmitting or receiving radio signals carrying information and/or data, signals, messages, etc., and a wireless communication system. It is operatively connected to components such as the memories 12 and 22 storing various information related to communication, the RF units 13 and 23, and the memories 12 and 22, and controls the components so that the corresponding device and processors 11 and 21 configured to control the memories 12 and 22 and/or the RF units 13 and 23 to perform at least one of the above-described embodiments of the present invention.

The memories 12 and 22 may store programs for processing and control of the processors 11 and 21 and may temporarily store input/output information. Memory 12, 22 may be utilized as a buffer. The processors 11 and 21 typically control the overall operation of various modules in a transmission device or a reception device. In particular, the processors 11 and 21 may perform various control functions for performing the present invention. The processors 11 and 21 may also be called a controller, a microcontroller, a microprocessor, a microcomputer, or the like. The processors 11 and 21 may be implemented by hardware, firmware, software, or a combination thereof. In the case of implementing the present invention using hardware, ASICs (application specific integrated circuits) or DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs ( field programmable gate arrays) may be provided in the processors 11 and 21. On the other hand, when the present invention is implemented using firmware or software, the firmware or software may be configured to include modules, procedures, or functions that perform the functions or operations of the present invention, and configured to perform the present invention. Firmware or software may be included in the processors 11 and 21 or stored in the memories 12 and 22 and driven by the processors 11 and 21 .

The processor 11 of the transmission device 10 performs predetermined coding and modulation on signals and/or data to be scheduled from the processor 11 or a scheduler connected to the processor 11 and transmitted to the outside. After performing, it is transmitted to the RF unit 13. For example, the processor 11 converts a data stream to be transmitted into K layers through demultiplexing, channel coding, scrambling, and modulation processes. The coded data sequence is also referred to as a codeword and is equivalent to a transport block, which is a data block provided by the MAC layer. One transport block (TB) is coded with one codeword, and each codeword is transmitted to a receiving device in the form of one or more layers. For frequency up-conversion, the RF unit 13 may include an oscillator. The RF unit 13 may include Nt transmit antennas (Nt is a positive integer greater than or equal to 1).

The signal processing process of the receiving device 20 is composed of the reverse of the signal processing process of the transmitting device 10. Under the control of the processor 21, the RF unit 23 of the receiver 20 receives the radio signal transmitted by the transmitter 10. The RF unit 23 may include Nr number of receiving antennas, and the RF unit 23 frequency down-converts each signal received through the receiving antennas to restore a baseband signal. The RF unit 23 may include an oscillator for frequency down conversion. The processor 21 may perform decoding and demodulation on the radio signal received through the reception antenna to restore data originally intended to be transmitted by the transmitter 10.

The RF units 13 and 23 have one or more antennas. The antenna, according to an embodiment of the present invention under the control of the processors 11 and 21, transmits signals processed by the RF units 13 and 23 to the outside, or receives a radio signal from the outside so that the RF unit 13 , 23). An antenna is also called an antenna port. Each antenna corresponds to one physical antenna or may be configured by a combination of more than one physical antenna element. A signal transmitted from each antenna cannot be further decomposed by the receiving device 20. The reference signal (RS) transmitted corresponding to the corresponding antenna defines the antenna viewed from the point of view of the receiving device 20, and whether the channel is a single radio channel from one physical antenna or includes the antenna Regardless of whether it is a composite channel from a plurality of physical antenna elements, the receiver 20 enables channel estimation for the antenna. That is, an antenna is defined such that a channel carrying a symbol on that antenna can be derived from the channel carrying another symbol on the same antenna. In the case of an RF unit supporting a multi-input multi-output (MIMO) function for transmitting and receiving data using a plurality of antennas, two or more antennas may be connected.

In the embodiments of the present invention, a terminal or UE operates as a transmitter 10 in uplink and as a receiver 20 in downlink. In the embodiments of the present invention, a base station or eNB operates as a receiving device 20 in uplink and as a transmitter 10 in downlink.

The transmitting device and/or the receiving device may perform at least one or a combination of two or more embodiments or proposals of the above-described embodiments of the present invention.

Detailed descriptions of the preferred embodiments of the present invention disclosed as described above are provided to enable those skilled in the art to implement and practice the present invention. Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will understand that the present invention described in the claims below can be variously modified and changed. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (24)

In a method for operating a terminal in a wireless communication system,
At a specific DCI timing in a plurality of downlink control information (DCI) timing sets, receiving a first DCI for scheduling downlink data in a first cell group including at least some of a plurality of cells configured in the terminal, ,
The first DCI includes a downlink assignment index (DAI) value,
The DAI value is determined from an initial DCI timing over all cells included in the first cell group except for cells of a second cell group different from the first cell group among a plurality of cells configured in the terminal. related to the cumulative total number of DCIs allocated to the terminal on the time axis up to a specific DCI timing;
Receiving the downlink data based on the first DCI; and
Transmitting control information including an acknowledgment/negative acknowledgment (ACK/NACK) response for the downlink data based on the DAI value;
When a plurality of DCIs including the first DCI are received through the first cell group at the specific DCI timing, the DAI value included in each of the plurality of DCIs is determined by the first scheduled DCI timing at the specific DCI timing. Same method for all cells of the cell group. According to claim 1,
The specific DCI timing is after the initial DCI timing. According to claim 1,
Another DCI for downlink scheduling is received at another DCI timing before the specific DCI timing in the plurality of DCI timing sets. According to claim 1,
The specific DCI timing comprises one or more consecutive orthogonal frequency division multiplexing (OFDM) symbols within a slot. According to claim 1,
The first DCI is received through a Physical Downlink Control Channel (PDCCH), the downlink data is received through a Physical Downlink Shared Channel (PDSCH), and the control information is transmitted through a Physical Uplink Control Channel (PUCCH),
The specific DCI timing in the plurality of DCI timing sets comprises: a specific PDCCH monitoring opportunity in a plurality of PDCCH monitoring opportunity sets. According to claim 5,
The DAI value is related to the cumulative value of PDSCHs allocated to the terminal on the time axis up to the PDSCH reception point in the cell group,
Coding HARQ-ACK (hybrid automatic repeat request, HARQ, acknowledgment) information for the first cell group based on the cumulative number of PDSCH transmissions;
Transmitting the coded HARQ-ACK information through a Physical Uplink Control Channel (PUSCH). In the apparatus for a terminal in a wireless communication system,
Memory; and
It includes a processor, the processor comprising:
At a specific DCI timing in a plurality of downlink control information (DCI) timing sets, a first DCI for scheduling of downlink data in a first cell group including at least some of a plurality of cells configured in the terminal is received,
The first DCI includes a downlink assignment index (DAI) value,
The DAI value is determined from an initial DCI timing over all cells included in the first cell group except for cells of a second cell group different from the first cell group among a plurality of cells configured in the terminal. related to the cumulative total number of DCIs allocated to the terminal on the time axis up to a specific DCI timing;
Receiving the downlink data based on the first DCI; and
Based on the DAI value, configured to transmit control information including an acknowledgment/negative acknowledgment (ACK/NACK) response for the downlink data,
When a plurality of DCIs including the first DCI are received through the first cell group at the specific DCI timing, the DAI value included in each of the plurality of DCIs is determined by the first scheduled DCI timing at the specific DCI timing. Same device for all cells of a cell group. According to claim 7,
The specific DCI timing is after the initial DCI timing. According to claim 7,
Another DCI for downlink scheduling is received at another DCI timing before the specific DCI timing in the plurality of DCI timing sets. According to claim 7,
The specific DCI timing includes one or more consecutive orthogonal frequency division multiplexing (OFDM) symbols within a slot. According to claim 7,
The first DCI is received through a Physical Downlink Control Channel (PDCCH), the downlink data is received through a Physical Downlink Shared Channel (PDSCH), and the control information is transmitted through a Physical Uplink Control Channel (PUCCH),
The specific DCI timing in the plurality of DCI timing sets comprises: a specific PDCCH monitoring opportunity in a plurality of PDCCH monitoring opportunity sets. According to claim 11,
The DAI value is related to the cumulative value of PDSCHs allocated to the terminal on the time axis up to the PDSCH reception point in the cell group,
Coding HARQ-ACK (hybrid automatic repeat request, HARQ, acknowledgment) information for the first cell group based on the cumulative number of PDSCH transmissions;
Transmitting the coded HARQ-ACK information through a Physical Uplink Control Channel (PUSCH). In the method of operating a base station in a wireless communication system,
At a specific DCI timing in a plurality of downlink control information (DCI) timing sets, transmitting a first DCI for scheduling of downlink data in a first cell group including at least some of a plurality of cells,
The first DCI includes a downlink assignment index (DAI) value,
The DAI value is determined from the initial DCI timing to the specific DCI timing over all cells included in the first cell group except for cells of a second cell group different from the first cell group among the plurality of cells. Up to, related to the cumulative total number of DCIs allocated to one terminal on the time axis;
Transmitting the downlink data corresponding to the first DCI; and
Receiving control information including an acknowledgment/negative acknowledgment (ACK/NACK) response for the downlink data based on the DAI value;
When a plurality of DCIs including the first DCI are transmitted through the first cell group at the specific DCI timing, the DAI value included in each of the plurality of DCIs corresponds to the first scheduled at the specific DCI timing. Same method for all cells of the cell group. According to claim 13,
The specific DCI timing is after the initial DCI timing. According to claim 13,
Another DCI for downlink scheduling is transmitted at another DCI timing before the specific DCI timing in the plurality of DCI timing sets. According to claim 13,
The specific DCI timing comprises one or more consecutive orthogonal frequency division multiplexing (OFDM) symbols within a slot. According to claim 13,
The first DCI is transmitted through a physical downlink control channel (PDCCH), the downlink data is transmitted through a physical downlink shared channel (PDSCH), and the control information is received through a physical uplink control channel (PUCCH),
The specific DCI timing in the plurality of DCI timing sets comprises: a specific PDCCH monitoring opportunity in a plurality of PDCCH monitoring opportunity sets. According to claim 17,
The DAI value is related to the cumulative value of PDSCHs allocated to the terminal on the time axis up to the PDSCH reception point in the cell group,
Receiving HARQ-ACK (hybrid automatic repeat request, HARQ, acknowledgment) information coded for the first cell group through a physical uplink control channel (PUSCH);
And decoding the coded HARQ-ACK information based on the accumulated number of PDSCH transmissions. In the apparatus for a base station in a wireless communication system,
Memory; and
It includes a processor, the processor comprising:
Transmitting a first DCI for scheduling of downlink data in a first cell group including at least some of a plurality of cells at a specific DCI timing in a plurality of downlink control information (DCI) timing sets,
The first DCI includes a downlink assignment index (DAI) value,
The DAI value is determined from the initial DCI timing to the specific DCI timing over all cells included in the first cell group except for cells of a second cell group different from the first cell group among the plurality of cells. Up to, related to the cumulative total number of DCIs allocated to one terminal on the time axis;
Transmitting the downlink data corresponding to the first DCI; and
Based on the DAI value, configured to receive control information including an acknowledgment/negative acknowledgment (ACK/NACK) response for the downlink data,
When a plurality of DCIs including the first DCI are transmitted through the first cell group at the specific DCI timing, the DAI value included in each of the plurality of DCIs corresponds to the first scheduled at the specific DCI timing. Same device for all cells of a cell group. According to claim 19,
The specific DCI timing is after the initial DCI timing. According to claim 19,
Another DCI for downlink scheduling is transmitted at another DCI timing before the specific DCI timing in the plurality of DCI timing sets. According to claim 19,
The specific DCI timing includes one or more consecutive orthogonal frequency division multiplexing (OFDM) symbols within a slot. According to claim 19,
The first DCI is transmitted through a physical downlink control channel (PDCCH), the downlink data is transmitted through a physical downlink shared channel (PDSCH), and the control information is received through a physical uplink control channel (PUCCH),
The specific DCI timing in the plurality of DCI timing sets comprises: a specific PDCCH monitoring opportunity in a plurality of PDCCH monitoring opportunity sets. delete

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